Water-absorbing agent composition and method for production thereof, absorptive article and absorbing material

ABSTRACT

The present invention has an object to provide a particulate water-absorbing composition, a production process therefor, and an absorbent article comprising this particulate water-absorbing composition, wherein the particulate water-absorbing composition causes little coloring of other materials and further is of high safety, and can provide excellent deodorizability and excellent absorption properties to absorbent articles such as diapers in the case where combined into the absorbent articles. As a means of achieving this object, a particulate water-absorbing composition according to the present invention is characterized by comprising a plant powder and a water-absorbent resin, wherein a surface portion and/or its vicinity of the water-absorbent resin is surface-treated with a crosslinking agent, and wherein the particulate water-absorbing composition exhibits an offensive-odor removal index of not less than 180 wherein the offensive-odor removal index is represented by the following equation: offensive-odor removal index=1.1×hydrogen sulfide removal ratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

TECHNICAL FIELD

The present invention relates to a particulate water-absorbingcomposition, an absorbent article, and an absorbent structure, whereinthe absorbent article and the absorbent structure comprise theparticulate water-absorbing composition. More specifically, theinvention relates to a particulate water-absorbing composition, anabsorbent article, and an absorbent structure wherein the particulatewater-absorbing composition can provide especially excellentdeodorizability and excellent absorption properties, and further, gelstability, to absorbent structures for sanitary materials such asdisposable diapers, sanitary napkins and incontinent pads in the casewhere used in the absorbent structures.

BACKGROUND ART

In recent years, water-absorbent resins are widely used as amongcomponents of sanitary materials, such as disposable diapers, sanitarynapkins and incontinent pads, for the purpose of causing the waterabsorbent resins to absorb body liquids.

As to the above water-absorbent resins, the following are known as theirexamples: partially-neutralized and crosslinked poly(acrylic acids);hydrolyzed graft polymers of starch-acrylonitrile; neutralized graftpolymers of starch-acrylic acid; saponified copolymers of vinylacetate-acrylate esters; crosslinked polymers of carboxymethylcellulose; hydrolyzed copolymers of acrylonitrile or acrylamide, orcrosslinked polymers of these hydrolyzed copolymers; crosslinkedpolymers of cationic monomers; crosslinked copolymers ofisobutylene-maleic acid; and crosslinked copolymers of2-acrylamido-2-methylpropanesulfonic acid-acrylic acid.

It is said that the above water-absorbent resins are desired to havewater absorption properties such as, upon contact with aqueous liquids(e.g. body fluids), high absorption capacity, excellent absorption rate,liquid permeability, gel strength of swollen gel, and suction quantityto suck up water from a base material containing aqueous liquids.

In addition to the above, various attempts are made to provide addedfunctions to the water-absorbent resins by adding thereto deodorizableand antibacterial compounds.

The deodorization is one of performances desirable to absorbentarticles, and studies are made to enhance the deodorizability of thewater-absorbent resins. Proposed as methods for providing thedeodorizability are, for example, methods in which the water-absorbentresins are allowed to contain the follow materials: active carbon(JP-A-105448/1984); extracts from leaves of Theaceae plants(JP-A-158861/1985); essences extracted from coniferous trees(JP-A-241030/1999); manufactured tea (JP-A-041155/1990); tannic acid andcomplex silicate salt compounds (JP-A-116829/1999).

However, as to the method in which the water-absorbent resins areallowed to contain the active carbon (JP-A-105448/1984), there areproblems in that the deodorizing effect is displayed by adsorption ofmalodorous components to the active carbon, but that the absorbency ofthe active carbon deteriorates with the passage of time so much that theactive carbon becomes deactivated in a period of from the provision toabsorbent articles till absorption of urine by the absorbent articlesduring their practical use. In addition, there are also significantproblems in that the active carbon causes black coloring of diapers inthe case where used for the diapers.

As to the method in which the water-absorbent resins are allowed tocontain the extracts from leaves of Theaceae plants (JP-A-158861/1985),the problems of coloring are improved, but the effect during thepractical use is low. In addition, production costs increase because ofthe extraction from leaves of plants.

As to the method in which the water-absorbent resins are allowed tocontain the essences extracted from coniferous trees (JP-A-241030/1999),essential oils such as essences extracted from trees have strong smellspeculiar to them and therefore, during the practical use, for example,display a high deodorizing effect of rendering the odor of urineindistinguishable. In such a case, the deodorizing effect is mainly froman odor-masking effect. The deodorization by masking involves the smellspeculiar to the essential oils. And there are differences betweenindividuals' tastes for smells, so the essential oils are not suitableas consumer materials aimed at many people. In addition, the essentialoils involve production costs.

As to the method in which the water-absorbent resins are allowed tocontain the tannic acid and the complex silicate salt compounds(JP-A-116829/1999), the removal effect is displayed upon specificmalodorous substances, but the deodorizing effect during the practicaluse of absorbent articles cannot be said to be enough, probably becausethere is no effect upon bad smells included in actual body fluids suchas urine.

As to the method in which the water-absorbent resins are allowed tocontain the manufactured tea (JP-A-041155/1990), the deodorizing effectof the manufactured tea itself is good, but still the deodorizing effectduring the practical use of absorbent articles could not be said to beenough, probably because of performances of water-absorbent resins beingused.

In addition, by reason of the use for such as absorbent articles, theprovision with the deodorizability is always desired to involve highsafety.

DISCLOSURE OF THE INVENTION Object of the Invention

An object of the present invention is to provide a particulatewater-absorbing composition, a production process therefor, an absorbentarticle, and an absorbent structure, wherein the particulatewater-absorbing composition causes little coloring of other materialsand further is of high safety, and can provide excellent deodorizabilityand excellent absorption properties to absorbent articles such asdiapers in the case where combined into the absorbent articles.

SUMMARY OF THE INVENTION

The present inventors diligently studied water-absorbing agents from thepoint of view of excellent deodorizability and excellent absorptionproperties in the case where the water-absorbing agents are combinedinto absorbent articles such as diapers. As a result, the inventors havecompleted the present invention by finding out that if a plant powderand a water-absorbent resin which has specific properties are combinedtogether to provide specific performance, then the above object can beachieved.

That is to say, a particulate water-absorbing composition, according tothe present invention, is characterized by comprising a plant powder anda water-absorbent resin, wherein a surface portion and/or its vicinityof the water-absorbent resin is surface-treated with a crosslinkingagent, and wherein the particulate water-absorbing composition exhibitsan offensive-odor removal index of not less than 180 wherein theoffensive-odor removal index is represented by the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

In the above particulate water-absorbing composition according to thepresent invention, the plant powder favorably comprises a powder of aTracheophyta plant, or a spice, or a tea leaf and/or a residue ofextraction therefrom.

In the above particulate water-absorbing composition according to thepresent invention, the content of the plant powder is favorably in therange of 0.001 to 20 weight parts per 100 weight parts of the solidcontent of the water-absorbent resin.

The above particulate water-absorbing composition, according to thepresent invention, favorably exhibits an absorption capacity of 25 to 60g/g, a suction index of not less than 14 g/g under a load, and anabsorption rate of not more than 60 seconds.

In addition, another particulate water-absorbing composition, accordingto the present invention, is characterized by: comprising a plant powderand a water-absorbent resin; and exhibiting an absorption capacity of 25to 60 g/g, a suction index of not less than 14 g/g under a load, and anabsorption rate of not more than 60 seconds; and exhibiting anoffensive-odor removal index of not less than 180 wherein theoffensive-odor removal index is represented by the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

The particulate water-absorbing composition, according to the presentinvention, is favorably used for sanitary materials.

A process for producing a particulate water-absorbing composition,according to the present invention, is characterized by comprising thestep of adding a plant powder to a water-absorbent resin that exhibitsan absorption capacity of 25 to 60 g/g, a suction power of not less than9 g/g under a load, and an absorption rate of not more than 60 seconds.

An absorbent article, according to the present invention, comprises anabsorbent layer, a liquid-permeable surface sheet, and aliquid-impermeable back sheet, wherein the absorbent layer includes thepresent invention particulate water-absorbing composition.

An absorbent structure, according to the present invention, comprises ahydrophilic fiber, a plant powder, and a water-absorbent resin; and ischaracterized by exhibiting an offensive-odor removal index of not lessthan 180 as a particulate water-absorbing composition including amixture of the plant powder and the water-absorbent resin, wherein theoffensive-odor removal index is represented by the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

The absorbent structure, according to the present invention, favorablycomprises the particulate water-absorbing composition in which the plantpowder is held by the water-absorbent resin.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention is explained in detail.

Used as the water-absorbent resin in the present invention is favorablya water-absorbent resin of which a surface portion and/or its vicinityis surface-treated with a crosslinking agent, specifically, treated bycrosslinking with a crosslinking agent reactable with a functional groupof the water-absorbent resin, and/or which exhibits an absorptioncapacity of 25 to 60 g/g, a suction power of not less than 9 g/g under aload, and an absorption rate of not more than 60 seconds.

As to the absorption properties of the water-absorbent resin, it isfavorable, for enhancing the effect of providing the deodorizability tothe whole diaper, to combine together a plant powder and awater-absorbent resin which satisfies all the properties such as theabsorption capacity of 25 to 60 g/g, the suction power of not less than9 g/g under a load, and the absorption rate of not more than 60 seconds.Although not clear, the cause is considered to be probably that if thewater-absorbent resin is limited to such as exhibits the specificabsorption capacity, suction power under a load, and absorption rate andif such a water-absorbent resin is combined with the plant powder, thenthe optimum balance between the action of the plant powder and theliquid absorption upon contact with urine is achieved.

The water-absorbent resin of which a surface portion and/or its vicinityis surface-crosslinked with a crosslinking agent, used in the presentinvention, is generally obtained by a production process comprising thestep of subjecting a water-absorbent resin to a surface-crosslinkingtreatment.

The water-absorbent resin in the present invention means awater-swellable and water-insoluble crosslinked polymer which absorbswater to form an anionic, nonionic, cationic, or their hybridwater-insoluble hydrogel. In addition, the particulate water-absorbingcomposition, as referred to in the present invention, means a materialwhich contains the water-absorbent resin in a major proportion,favorably, of not less than 70 weight %, more favorably, of not lessthan 80 weight %, and absorbs water.

Incidentally, the term “water-swellable” means that the material is ableto absorb at least 2 times, favorably 10 to 3,000 times, more favorably50 to 2,000 times, as large a quantity of water as its own weight (solidcontent) in ion-exchanged water, and the term “water-insoluble” meansthat the uncrosslinked water-extractable content in the water-absorbentresin is not more than 50 weight %, favorably not more than 25 weight %,more favorably not more than 20 weight %, still more favorably not morethan 15 weight %, particularly favorably not more than 10 weight %.

A method for measuring the water-extractable content is specified inEDANA RECOMMENDED TEST METHODS 470, 1-99 EXTRACTABLES of EUROPEANDISPOSABLES AND NONWOVENS ASSOCIATION.

Examples of such water-absorbent resins include one or mixtures of thefollowing materials: partially-neutralized and crosslinked poly(acrylicacids); hydrolyzed graft polymers of starch-acrylonitrile; neutralizedgraft polymers of starch-acrylic acid; saponified copolymers of vinylacetate-acrylate esters; hydrolyzed copolymers of acrylonitrile oracrylamide, or crosslinked polymers of these hydrolyzed copolymers;modified polymers of carboxyl-group-containing crosslinked poly(vinylalcohols); and crosslinked copolymers of isobutylene-maleic anhydride.

These water-absorbent resins may be used either alone respectively or incombinations with each other, but, in particular, one or mixtures ofthose which have a carboxyl group are favorable, and it is typicallyfavorable that the water-absorbent resin comprises a polymer(water-swellable crosslinked polymer of poly(acrylic acid (salt))) asthe main component which polymer is obtained by a process including thesteps of polymerizing monomers including acrylic acid and/or its salt(neutralized product) as the main component and then crosslinking theresultant polymer. In addition, these water-absorbent resins may beeither water-containing hydrogels, or powders obtained by a processincluding the steps of: drying the hydrogels, if necessary; and usuallypulverizing them before and/or after the drying step.

The above-mentioned water-absorbent resin, for example, can be obtainedby a process including the steps of: polymerizing or copolymerizing atlease one monomer selected from the group consisting of unsaturatedcarboxylic acids, such as (meth)acrylic acid, maleic acid, maleicanhydride, fumaric acid, crotonic acid, itaconic acid, andβ-acryloyloxypropionic acid, and neutralized products thereof; and then,if need be, subjecting the resultant polymer to operations, such aspulverization and classification, to arrange its particle diameters.

The neutralization ratio of the above acid group is favorably adjustedinto the range of 30 to 100 mol %, more favorably 60 to 90 mol %, stillmore favorably 65 to 75 mol %. The neutralization of the acid group maybe carried out either by neutralization of an acid-group-containingmonomer in an aqueous solution before polymerization, or byneutralization of an aqueous solution of the polymer, in other words, bypost-neutralization of a polymer gel, or both neutralizations may beused jointly with each other. Favorable examples of salts beingneutralized include those of sodium, lithium, potassium, ammonia, andamines.

As to the monomer, (meth)acrylic acid and their neutralized products arepreferable of the above monomers. The weight-average particle diameteris favorably in the range of 100 to 600 μm, more favorably 200 to 500μm, and the proportion of particles having particle diameters of smallerthan 106 μm is not more than 10 weight %, favorably not more than 5weight %, more favorably not more than 3 weight %.

Furthermore, the above-mentioned water-absorbent resin may be acopolymer of the above-mentioned monomer and another monomercopolymerizable therewith. Specific examples of the above other monomerinclude: anionic unsaturated monomers, such as vinylsulfonic acid,styrenesulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid,2-(meth)acryloylethanesulfonic acid, and 2-(meth)acryloylpropanesulfonicacid, and salts thereof, nonionic hydrophilic-group-containingunsaturated monomers such as acrylamide, methacrylamide,N-ethyl(meth)acrylamide, N-n-propyl(meth)acrylamide,N-isopropyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide,2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate,methoxypolyethylene glycol (meth)acrylate, polyethylene glycolmono(meth)acrylate, vinylpyridine, N-vinylpyrrolidone,N-acryloylpiperidine, and N-acryloylpyrrolidine; and cationicunsaturated monomers such as N,N-dimethylaminoethyl(meth)acrylate,N,N-diethylaminoethyl(meth)acrylate,N,N-dimethylaminopropyl(meth)acrylate,N,N-dimethylaminopropyl(meth)acrylamide, and quaternary salts thereof.

It is favorable that the water-absorbent resin is such as internallycrosslinked by a reaction or copolymerization with a crosslinking agenthaving at least two polymerizable unsaturated groups or at least tworeactive groups. In addition, the water-absorbent resin may be aself-crosslinking type which does not need any crosslinking agent.

Specific examples of the above crosslinking agent (which might bereferred to as internal-crosslinking agent) includeN,N′-methylenebis(meth)acrylamide, (poly)ethylene glycoldi(meth)acrylate, (poly)propylene glycol di(meth)acrylate,trimethylolpropane di(meth)acrylate, trimethylolpropanetri(meth)acrylate, glycerol tri(meth)acrylate, glycerol acrylatemethacrylate, ethylene-oxide-modified trimethylolpropanetri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol hexa(meth)acrylate, triallyl cyanurate, triallylisocyanurate, triallyl phosphate, triallylamine,poly(meth)allyloxyalkanes, (poly)ethylene glycol diglycidyl ether,glycerol diglycidyl ether, ethylene glycol, polyethylene glycol,propylene glycol, glycerol, pentaerythritol, ethylenediamine,polyethylenimine, and glycidyl(meth)acrylate. These crosslinking agentsmay be used either alone respectively or in combinations with eachother. Among the above exemplifying compounds, those which have at leasttwo polymerizable unsaturated groups are preferably used as thecrosslinking agents.

The amount of the crosslinking agent as used is favorably in the rangeof 0.01 to 2 mol %, more favorably 0.03 to 0.2 mol %, of the total ofthe above-mentioned monomers. In the case where the amount of thecrosslinking agent as used is smaller than 0.01 mol %, caution isneeded, because it might be difficult to obtain the properties such asthe suction power of not less than 9 g/g under a load by thebelow-mentioned surface-crosslinking treatment.

In addition, usable when the above polymerization is initiated are, forexample, as follows: radical polymerization initiators such as potassiumpersulfate, ammonium persulfate, sodium persulfate, t-butylhydroperoxide, hydrogen peroxide, and 2,2′-azobis(2-amidinopropane)dihydrochloride; or active energy rays such as ultraviolet rays andelectron beams. In addition, when oxidizable radical polymerizationinitiators are used, redox polymerization can, for example, be carriedout using jointly therewith reducing agents such as sodium sulfite,sodium hydrogensulfite, ferrous sulfate, and L-ascorbic acid. The amountof these polymerization initiators as used is favorably in the range of0.001 to 2 mol %, more favorably 0.01 to 0.5 mol %.

In addition, also favorable is a way in which such as foaming agents(e.g. carbonate salts, azo compounds) or inert gases are added into themonomer during the polymerization in order for the resultantwater-absorbent resin to have a porous structure, therefore, anincreased specific surface area.

In addition, as to the process for producing the water-absorbent resinin the present invention, for example, in cases of aqueous solutionpolymerization, the process includes the following sequential steps of:arrangement of aqueous monomer solution—polymerization—fineparticulation of polymer—drying—pulverization—classification.

In the case where the above aqueous solution polymerization is carriedout, an aqueous monomer solution having a concentration of generally 10weight % to saturation, favorably 20 to 60 weight %, is arranged andthen polymerized. As to the polymerization method, examples thereofinclude: a method in which the polymerization is carried out in atwin-arm kneader while agitation is carried out if necessary; a methodin which cast polymerization is carried out in a container; and a methodin which static polymerization is (continuously) carried out on a movingbelt.

For drying the polymer (hydrogel) resultant from the abovepolymerization step, it is desirable to finely particulate this hydrogelinto predetermined particle diameters. The fine particulation of thehydrogel can be carried out during the polymerization by doing thepolymerization under stirred conditions with such as twin-arm kneaders,or can be carried out by extruding the gel from dies with such as meatchoppers after the polymerization. In addition, the fine particulationcan also be carried out with such as cutting mills. The particlediameters of the finely particulated gel can fitly be set according tosuch as ability of driers, but is generally preferably in the range of0.1 to 10 mm. In the case where the gel is finer than 0.1 mm, theproperties of the resultant water-absorbent resin might be inferior. Inthe case where the gel is coarser than 10 mm, the gel might be difficultto dry.

In the fine particulation step, a coarse gel with particle diameterslarger than 10 mm and a fine gel with particle diameters smaller than0.1 mm might form. These polymers can be separated and then added tosuch as an aqueous monomer solution or a polymer gel.

The gel as finely particulated in the above fine particulation step isdried in the drying step. Examples of usable means for drying includehot-air driers, air blow type (pneumatic type) driers, azeotropicdehydration, fluidized-bed driers, drum driers, microwaves, and farinfrared rays. The drying temperature is favorably not lower than 80°C., more favorably not lower than 120° C., still more favorably in therange of 150 to 250° C., yet still more favorably in the range of 160 to220° C.

The above-mentioned water-absorbent resin may be granulated into apredetermined shape and can have various shapes such as spheres, scales,irregular pulverized shapes, and granules. Furthermore, thewater-absorbent resin may comprise either substantially ungranulatedprimary particles or a granulated matter thereof.

The above-mentioned water-absorbent resin generally does not satisfy therequirements of the present invention for the ranges of the absorptioncapacity, the suction power under a load, and the water absorption rate.Therefore, the crosslinking density in the vicinity of surfaces of thewater-absorbent resin needs to be rendered higher than that inside thewater-absorbent resin by further using a crosslinking agent. In otherwords, water absorbent resins usable in the present invention areobtained by crosslinking the vicinity of surfaces of the water-absorbentresin with the crosslinking agent.

In the present invention, obtainable from these water-absorbent resinsare a water-absorbent resin of which a surface portion and/or itsvicinity is treated by crosslinking, and/or a water-absorbent resinwhich exhibits an absorption capacity of 25 to 60 g/g, a suction powerof not less than 9 g/g under a load, and a water absorption rate of notmore than 60 seconds.

Thus, the water-absorbent resin, according to the present invention, isfavorably obtained by a process including the step of thermally treatingthe foregoing water-absorbent resin in the presence of the crosslinkingagent reactable with a functional group of the water-absorbent resin(hereinafter such a crosslinking agent is referred to assurface-crosslinking agent) wherein the foregoing water-absorbent resinis a water-absorbent resin as obtained by the aqueous solutionpolymerization or reversed-phase suspension polymerization, favorablythe aqueous solution polymerization, that is, a water-absorbent resin asobtained by making arrangements involving the operations such aspolymerization and classification so that the weight-average particlediameter may be in the range of 100 to 600 μm, more favorably 200 to 500μm, and that the proportion of particles having particle diameters ofsmaller than 106 μm may not be more than 10 weight %, favorably not morethan 5 weight %, more favorably not more than 3 weight %.

The above surface-crosslinking agent is what has a functional groupreactable with a functional group, such as acid group, of thewater-absorbent resin, and examples thereof include conventionalcrosslinking agents which are usually used for the correspondingpurpose.

In the case where the functional group of the water-absorbent resin isfor example a carboxyl group, examples of the surface-crosslinking agentinclude one or more members selected from the group consisting of:polyhydric alcohol compounds such as ethylene glycol, diethylene glycol,propylene glycol, triethylene glycol, tetraethylene glycol, polyethyleneglycol, 1,3-propanediol, dipropylene glycol,2,2,4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerol,polyglycerol, 2-butene-1,4-diol, 1,4-butanediol, 1,5-pentanediol,1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,2-cyclohexanol,trimethylolpropane, diethanolamine, triethanolamine, polyoxypropylene,oxyethylene-oxypropylene block copolymers, pentaerythritol and sorbitol;epoxy compounds such as ethylene glycol diglycidyl ether, polyethyleneglycol diglycidyl ether, glycerol polyglycidyl ether, diglycerolpolyglycidyl ether, polyglycerol polyglycidyl ether, propylene glycoldiglycidyl ether, polypropylene glycol diglycidyl ether and glycidol;polyamine compounds such as ethylenediamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine,polyallylamine, and polyethylenimine; polyisocyanate compounds such as2,4-tolylene diisocyanate and hexamethylene diisocyanate; polyoxazolinecompounds such as 1,2-ethylenebisoxazoline; alkylene carbonate compoundssuch as 1,3-dioxolan-2-one, 4-methyl-1,3-dioxolan-2-one,4,5-dimethyl-1,3-dioxolan-2-one, 4,4-dimethyl-1,3-dioxolan-2-one,4-ethyl-1,3-dioxolan-2-one, 4-hydroxymethyl-1,3-dioxolan-2-one,1,3-dioxan-2-one, 4-methyl-1,3-dioxan-2-one,4,6-dimethyl-1,3-dioxan-2-one and 1,3-dioxopan-2-one; mono-, di-, orpolyoxazolidine compounds; haloepoxy compounds such as epichlorohydrin,epibromohydrin and α-methylepichlorohydrin; polyvalent metalliccompounds such as hydroxides and chlorides of such as zinc, calcium,magnesium, aluminum, iron and zirconium; silane coupling agents such asγ-glycidoxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane; andpolyamide-polyamine-epihalohydrin resins. Preferable are those whichinclude at least one member selected from the group consisting of thepolyhydric alcohol compounds, the polyamine compounds, the polyepoxycompounds, and the alkylene carbonate compounds.

The amount of the surface-crosslinking agent as used depends on factorssuch as the compounds as used as the surface-crosslinking agents orcombinations of such compounds, but is favorably in the range of 0.001to 5 weight parts, more favorably 0.01 to 1 weight part, per 100 weightparts of the solid content of the water-absorbent resin. If theabove-mentioned surface-crosslinking agents are used, the crosslinkingdensity in the vicinity of surfaces of the water-absorbent resin can berendered higher than that inside, thereby forming what has theabsorption properties which are required of the present invention resin.The amount larger than 10 weight parts of the surface-crosslinking agentas used is not only uneconomical, but also might be so excessive to theformation of the optimal crosslinked structure in the water absorbentresin as to unfavorably result in a low absorption capacity. Inaddition, in the case where the amount of the surface-crosslinking agentas used is smaller than 0.001 weight part, the suction power of thewater-absorbent resin under a load might be difficult to enhance.

When the water-absorbent resin and the surface-crosslinking agent aremixed together, water is preferably used as a solvent. The amount ofwater as used depends upon such as type or particle diameters of thewater-absorbent resin, but is favorably in the range of 0 to 20 weightparts (but not including 0 weight part), more favorably in the range of0.1 to 10 weight parts, per 100 weight parts of the solid content of thewater-absorbent resin.

In addition, when the water-absorbent resin and the surface-crosslinkingagent are mixed together, a hydrophilic organic solvent may be used as asolvent, if necessary. Examples of the above hydrophilic organic solventinclude: lower alcohols such as methyl alcohol, ethyl alcohol, n-propylalcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, andt-butyl alcohol; ketones such as acetone; ethers such as dioxane andtetrahydrofuran; amides such as N,N-dimethylformamide; and sulfoxidessuch as dimethyl sulfoxide. The amount of the hydrophilic organicsolvent as used depends upon such as type or particle diameters of thewater absorbent resin, but is favorably not larger than 20 weight parts,more favorably not larger than 10 weight parts, per 100 weight parts ofthe solid content of the water-absorbent resin.

Examples of methods for mixing the water-absorbent resin and thesurface-crosslinking agent together include a method comprising thesteps of dispersing the water-absorbent resin into the above hydrophilicorganic solvent, and then mixing the resultant dispersion with thesurface-crosslinking agent. However, the mixing method is not especiallylimited. Preferable among various mixing methods is a method comprisingthe step of spraying or dropwise adding the surface-crosslinking agent(as dissolved in water and/or the hydrophilic organic solvent, ifnecessary) directly onto the water-absorbent resin, thus mixing them. Inaddition, in the case where the mixing step is carried out using water,there may coexist such as water-insoluble finely-particulate powders orsurfactants.

A mixing apparatus, as used to mix the water-absorbent resin and thesurface-crosslinking agent together, favorably has great mixing power tohomogeneously and surely mix them. Preferable examples of the mixingapparatus include cylinder type mixers, double-wall cone type mixers,V-character-shaped mixers, ribbon type mixers, screw type mixers,fluidized type rotary disk type mixers, air blow type (pneumatic type)mixers, twin-arm kneaders, internal mixers, pulverizing type kneaders,rotary mixers, and screw type extruders.

Carrying out a thermal treatment, after mixing the water-absorbent resinprecursor and the surface-crosslinking agent together, is favorable forobtaining the water-absorbent resin as used in the present invention,specifically, the water-absorbent resin of which a surface portionand/or its vicinity is treated by crosslinking with a crosslinking agentreactable with a functional group of the water-absorbent resin, and/orwhich exhibits an absorption capacity of 25 to 60 g/g, a suction powerof not less than 9 g/g under a load, and an absorption rate of not morethan 60 seconds. The treatment temperature in this thermal treatmentdepends upon the surface-crosslinking agent as used, but is favorably inthe range of 40 to 250° C., more favorably 90 to 210° C. In the casewhere the treatment temperature is lower than 40° C., no uniformcrosslinked structure is formed and it might therefore be impossible toobtain the water-absorbent resin of which the suction power under a loadis in the range as defined by the present invention. In the case wherethe treatment temperature is higher than 250° C., caution is needed,because the water-absorbent resin might be degraded so much as to merelyexhibit low performance.

The above thermal treatment can be carried out with conventional driersor heating furnaces.

Examples of the driers include channel type mixing driers, rotarydriers, disk driers, fluidized-bed driers, air blow type (pneumatictype) driers, and infrared driers.

For obtaining the water-absorbent resin usable in the present invention,it is favorable to control such as crosslinking agent, mixing method,heating temperature, and treatment time, as mentioned above, so that thesuction power under a load may not be less than 9 g/g.

The particulate water-absorbing composition, according to the presentinvention, is obtained by the process including the step of adding theplant powder to the water-absorbent resin of which a surface portionand/or its vicinity is favorably surface-treated with a crosslinkingagent, and/or to the water-absorbent resin which resin exhibits anabsorption capacity of 25 to 60 g/g, favorably not less than 27 g/g,more favorably not less than 29 g/g, still more favorably not less than31 g/g, a suction power of not less than 9 g/g, favorably not less than10 g/g, more favorably not less than 11 g/g, under a load, and anabsorption rate of not more than 60 seconds, favorably not more than 55seconds, more favorably not more than 50 seconds, wherein thesewater-absorbent resins are obtained in the above ways.

A plant powder usable in the present invention comprises a powder of aTracheophyta (Spermatophyta, Pteridophyta) plant, a Bryophyta plant, oralgae, favorably, the powder of the Tracheophyta plant.

The plant powder usable in the present invention may be a productobtained by a process including the step of pulverizing a plant residuewhich is formed as a by-product in production processes in plant- andfood-processing industries if such a plant powder satisfies theperformance as required in the present invention.

It is also a favorable mode that the plant powder usable in the presentinvention comprises a spice, and further it is yet also a favorable modethat the plant powder usable in the present invention comprises a tealeaf and/or a residue of extraction therefrom.

In the present invention, there is no especial limitation with regard toportions being used of plants used as the plant powder if they satisfythe performance as required in the present invention. Such a portion is,for example, at least one portion selected from the group consisting ofsuch as leaves, branches, trunks, stalks, roots, fruits, flowers, seeds,and barks.

The particle size of the plant powder usable in the present invention issuch that the plant powder can pass through a mesh of which the meshopening size is 850 μm, favorably 600 μm, more favorably 500 μm, stillmore favorably 300 μm.

That is to say, the plant powder usable in the present invention is suchthat in the case where such a plant powder as passes through the meshhaving the mesh opening size of 850 μm is used for the particulatewater-absorbing composition, this particulate water-absorbingcomposition can, as is mentioned below, exhibit an offensive-odorremoval index of not less than 180 wherein the offensive-odor removalindex is represented by the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

The aspect ratio of the plant powder usable in the present invention(which is a value as calculated from the following equation: aspectratio=length/breadth wherein the length and the breadth are those of theplant powder) is favorably in the range of 1 to 50 (but not including50), more favorably 1 to 40 (but not including 40), still more favorably1 to 30 (but not including 30).

The water content of the plant powder usable in the present invention isnot especially limited, but is favorably not more than 40%, morefavorably not more than 30%, still more favorably not more than 20%, yetstill more favorably not more than 10%.

In the case where the plant powder usable in the present inventioncomprises the powder of the Tracheophyta plant, this Tracheophyta plantis favorably at least one kind of Tracheophyta plant selected from thegroup consisting of Gramineae, maple family, Ebenaceae, Betulaceae,Compositae, Lamiaceae, cryptomeria family, Umbelliferae, Rosaceae,Vitaceae, Japanese cypress family, pine family, Fagaceae, Brassicaceae,Leguminosae, Rutaceae, Cucurbitaceae, Solanaceae, Piperaceae,Zingiberaceae, Lauraceae, Malvaceac, and Theaceae.

Examples of the Tracheophyta plant on the Gramineae include rice plants,bamboo grasses, bamboos, maize, barley and wheat. Examples of theTracheophyta plant on the maple family include maples. Examples of theTracheophyta plant on the Ebenaceae include persimmons. Examples of theTracheophyta plant on the Betulaceae include hornbeams, hazels, birches,and alders. Examples of the Tracheophyta plant on the Compositae includechrysanthemums, burdocks, dandelions, and mugworts. Examples of theTracheophyta plant on the Lamiaceae include Utsubogusa (in Japanese)(herein the italics with “(in Japanese)” are as they are originalJapanese words, because no proper English equivalents therefor arefound), Egoma (in Japanese), Odorikoso (in Japanese), perillas, andpeppermint. Examples of the Tracheophyta plant on the cryptomeria familyinclude cryptomerias, China-Firs, and Taiwanese cryptomerias. Examplesof the Tracheophyta plant on the Umbelliferae include umbelliferousplants resembling stone parsley used in cooking for their aroma (mitsubain Japanese), carrots, parsley, and celery. Examples of the Tracheophytaplant on the Rosaceae include Japanese apricots (ume in Japanese),cherries, spireas, roses, apricots, pears, peaches, apples,strawberries, plums, hawthorns, loquats, raphiolepises, Japanesequinces, Kamatsuka (in Japanese) (Pourthiaea), mountain ashes, andkerrias. Examples of the Tracheophyta plant on the Vitaceae includegrapes, ivy, and wild grapes. Examples of the Tracheophyta plant on theJapanese cypress family include Japanese cypresses, arbor-vitaes, hibaarbor-vitaes, junipers, and sawara (in Japanese) cypresses(Chamaecyparis pisifera). Examples of the Tracheophyta plant on the pinefamily include larches, hemlock spruces, spruces, pines, firs, andHimalayan cedars. Examples of the Tracheophyta plant on the Fagaceaeinclude beeches, chestnuts, chinquapins, shirakashi (in Japanese)(Quercus myrsinaefolia), arakashi (in Japanese) (Quercus glauca), andurazirogashi (in Japanese) (Quercus salicina). Examples of theTracheophyta plant on the Brassicaceac include Japanese white radishesand rape. Examples of the Tracheophyta plant on the Leguminosae includeadzuki, licorice, broad beans, and soybeans. Examples of theTracheophyta plant on the Rutaceae include mandarins (mandarin oranges),oranges, grapefruits, shaddocks, Japanese pepper trees, citrons, lemons,and limes. Examples of the Tracheophyta plant on the Cucurbitaceaeinclude pumpkins, cucumbers, watermelons, loofahs, and bottle gourds.Examples of the Tracheophyta plant on the Solanaceae include eggplants,capsicums, green peppers, and tomatoes. Examples of the Tracheophytaplant on the Piperaceae include peppers. Examples of the Tracheophytaplant on the Zingiberaceae include ginger. Examples of the Tracheophytaplant on the Lauraceae include camphor trees, camphor, spice bushes,shiromoji (in Japanese) (Parabenzoin), laurels, shirodamo (in Japanese)(Neolitsea), and hamahiwa (in Japanese) (Litsea). Examples of theTracheophyta plant on the Malvaceae include hollyhocks, mallows, rosemallows, hibiscuses, kan-aoi (in Japanese), and kenafs. Examples of theTracheophyta plant on the Theaceae include camellias, scarlet sakaki (inJapanese) plants, sakaki (in Japanese) plants, and mokkoku (in Japanese)(Ternstroemia).

The spice usable in the present invention is such that seeds, fruits,buds, leaves, barks, or rhizomes of spice plants are dried and then,either intactly or after powdering, used to get them to serve as aseasoning or condiment for foods. So many spices are used for foods, andthe spice is produced naturally or by culture. The usable spice means aproduct obtained using a spice as a starting material, which product is,for example, a spice produced by intactly arranging the shape orparticles of its starting material, or a spice powder formed bypulverizing its starting material. The usable spice is not such as isobtained by separating only a single component from a spice, but such ascontains various components.

The spice favorably usable in the present invention is a spice havingdeodorizability, and is not especially limited, but can be exemplifiedby Tracheophyta plants such as ajowan, anises, fennels, turmeric,allspices, oreganos, mustard, cardamoms, caraways, cumin, cloves,peppers, corianders, saffron, Japanese peppers, perillas, cinnamons,ginger, cardamoms, ziiru (in Japanese), star anises, sage, onions,thyme, turmeric, cloves, dill, capsicums, nutmegs, nikuzuku (inJapanese) (nutmegs), garlic, peppermint, parsley, basil, paprika,vanillas, feneguriiku (in Japanese), fennels, mace, rosemary, laurier,laurels, and Japanese horseradishes. Of these spices, particularly,those which exhibit the deodorizability without the masking-likefunction are used favorably for providing the deodorizability withoutgiving wearers an unpleasant feeling in the case of uses for absorbentarticles. Above all, peppers, Japanese peppers, ginger, capsicums,parsley, and Japanese horseradishes are used especially favorably forthe present invention.

The shape of the above spices is different according to the aimeddeodorizability, but is powdery, and the size of their particles is suchthat they can pass through a mesh of which the mesh opening size is 850μm, favorably 600 μm, more favorably 500 μm, still more favorably 300μm, and further that the volume-average particle diameter is favorablynot larger than 850 μm, more favorably not larger than 600 μm, stillmore favorably not larger than 500 μm, yet still more favorably notlarger than 300 μm. Common liquid spices are unfavorable, because theymight be so aromatic as to give an unpleasant feeling. In addition, inthe case where the particle diameter is larger than 850 μm, the actionsof effective components contained in the spice might unfavorably beinsufficient to provide stable deodorizability during contact withurine. In addition, it is preferable that the volume-average particlediameter of the spice is smaller than the weight-average particlediameter of the water-absorbent resin, because more excellentdeodorizability can be provided in such a case.

The water content of the spice usable in the present invention is notespecially limited, but is favorably not more than 40%, more favorablynot more than 30%, still more favorably not more than 20%, yet stillmore favorably not more than 10%.

The tea leaf usable in the present invention is such as obtained byprocessing a plant which is a Tracheophyta plant so that it may be fitto drink. Examples thereof include agarisk tea, ashitaba-cha (inJapanese), hydrangea vine tea, aloe tea, ginkgo leaf tea, Araliaceaetea, turmeric tea, urazirogashi-cha (in Japanese) (Quercus stenophyllatea), oolong tea, plantain tea, persimmon leaf tea, licorice tea,chrysanthemum tea, gymnema tea, Chinese matrimony vine tea, low stripedbamboo tea, cranesbill tea, black tea, hawthorn tea, perillas tea,jasmine tea, sugina-cha (in Japanese), senna tea, mulberry leaf tea,buckwheat tea, tahibo-cha (in Japanese), dandelion tea, Chinese tea,tetsukannon-cha (in Japanese), ten-cha (in Japanese), tochu-cha (inJapanese), dokudami-cha (in Japanese), shepherd's purse tea, nandin tea,basera-cha (in Japanese), Banaba (Lagerstoemia Speciosa Pers) tea, adlaytea, loquat tea, Pu-erh tea, pine needle tea, parched barley tea,mugwort tea, green tea, gentian tea, and Rooibos tea, and, preferably,those which are obtained by processing evergreen low trees on theTheaceae and their leaves so that they may be fit to drink, such asgreen tea, black tea, and oolong tea.

The general value of the water content in the above tea leaf is, forexample, in the range of 6 to 9 g per 100 g of the tea leaf, but thewater content of the tea leaf as used in the present invention is notespecially limited, but tea leaves having various water contents areusable.

The residue of extraction from the tea leaf, usable in the presentinvention, can be exemplified by residues of extraction from the abovetea leaves, and, favorably, a dried product of the residue of extractionfrom the tea leaf is used. What is referred to as the dried product ofthe residue of extraction from the tea leaf in the present invention isan extraction residue which is left behind in extraction of tea from theabove tea leaf, and is a substantially dry one, of which the watercontent is not more than 40%, favorably not more than 30%, morefavorably not more than 20%, still more favorably not more than 10%.Having water contents in these ranges is favorable also for facilitationof handling of the extraction residue.

Fine powders which are formed as by-products in processes for productionof tea, or tea leaves and/or residues of extraction therefrom which aredischarged as the extraction residues being left behind in extraction oftea, are presently disposed of, and are therefore utilizable favorablyin aspects of such as effective utilization of resources or prices.

The shape of the above tea leaf and/or residue of extraction therefromis different according to the aimed deodorizability, but is powdery, andthe size of their particles is such that they can pass through a mesh ofwhich the mesh opening size is 850 μm, favorably 600 μm, more favorably500 μm, still more favorably 300 μm. The volume-average particlediameter is favorably not larger than 500 μm, more favorably not largerthan 300 μm. In the case where the volume-average particle diameter islarger than 500 μm, the actions of effective components contained in thetea leaf and/or residue of extraction therefrom might unfavorably beinsufficient to provide stable deodorizability during contact withurine. In addition, it is preferable that the volume-average particlediameter of the tea leaf and/or residue of extraction therefrom issmaller than the weight-average particle diameter of the water-absorbentresin, because more excellent deodorizability can be provided in such acase.

As to absorbent articles (such as diapers) in which conventionalwater-absorbent resins containing the above plant powder are used, someof those water-absorbent resins might provide the deodorizability to thewhole diaper so insufficiently as to give wearers an unpleasant feeling.However, the particulate water-absorbing composition according to thepresent invention solves the above problems by specifying the propertiesof a water-absorbent resin which has not yet been mixed with the plantpowder, and this particulate water-absorbing composition can provideexcellent deodorizability and excellent absorption properties toabsorbent articles and is favorably used for the absorbent articles.

In addition, as to conventional water-absorbent resins, the balancebetween their water absorption properties is being improved bysubjecting a surface portion and/or its vicinity of the water-absorbentresin to a crosslinking treatment with a crosslinking agent reactablewith a functional group of the water-absorbent resin, but, in the casewhere the water-absorbent resin is used in absorbent articles (such asdiapers), the water-absorbent resin might deteriorate with the passageof time so much as to provide inferior results with regard to the liquidpermeability, gel strength, or absorption properties. However, becauseof containing the plant powder, the particulate water-absorbingcomposition according to the present invention is surprisingly aparticulate water-absorbing composition which deteriorates little withthe passage of time after absorption of urine and exhibits excellent gelstability, and can provide excellent deodorizability and excellentabsorption properties to absorbent articles for a long time and isfavorably used for the absorbent articles.

The amount of the above plant powder as used is different according tothe aimed deodorizability, but the amount thereof as added is favorablyin the range of 0.001 to 20 weight parts, more favorably 0.01 to 10weight parts, still more favorably 0.01 to 5 weight parts, per 100weight parts of the solid content of the water-absorbent resin.

In addition, examples of methods for adding the above plant powderinclude: a method comprising the step of mixing the water-absorbentresin directly with the plant powder so that a desired amount of theplant powder may be added to the water-absorbent resin (for example, adry blend method in which powders are mixed together); a methodcomprising the steps of mixing the water-absorbent resin directly withthe plant powder, and then spraying or dropwise adding such as water,aqueous liquids, or various organic solvents onto the resultant mixture,thus mixing them; and a method comprising the steps of dispersing theplant powder into such as water, aqueous liquids, or various organicsolvents, and then spraying or dropwise adding the resultant dispersiondirectly onto the water-absorbent resin, thus mixing them. Incidentally,there can also be adopted the following methods: a method comprising thestep of adding the plant powder during the polymerization of thewater-absorbent resin; and a method comprising the step of adding theplant powder to the resultant gel after the polymerization. However, incases where these methods are adopted, they need to be carried out in away such that the resultant composition will satisfy the claimed rangesof the absorption capacity, the suction power under a load, and theabsorption rate as a result of the steps as thereafter carried out.

Particularly preferable of the above methods for adding the plant powderare as follows: the method comprising the steps of mixing thewater-absorbent resin directly with the plant powder, and then sprayingor dropwise adding such as water, aqueous liquids, or various organicsolvents onto the resultant mixture, thus mixing them; the methodcomprising the steps of dispersing the plant powder into such as water,aqueous liquids, or various organic solvents, and then spraying ordropwise adding the resultant dispersion directly onto thewater-absorbent resin, thus mixing them; the method comprising the stepof adding the plant powder during the polymerization of thewater-absorbent resin; and the method comprising the step of adding theplant powder to the resultant gel after the polymerization. Thesemethods give a form in which the plant powder is held by thewater-absorbent resin.

As to the present invention, in the case where the water-absorbent resinand the plant powder are mixed together, the optimum amount of such aswater, water vapor, or aqueous liquids including water and hydrophilicorganic solvents, which are added if necessary, is different accordingto the type or particle diameters of the water-absorbent resin. However,in the case of water, the amount thereof is usually not larger than 10weight parts, favorably in the range of 1 to 5 weight parts, per 100weight parts of the solid content of the water-absorbent resin. Inaddition, similarly, the amount of the hydrophilic organic solvent asused is usually not larger than 10 weight parts, favorably in the rangeof 0.1 to 5 weight parts, per 100 weight parts of the solid content ofthe water-absorbent resin.

The apparatus which is used to mix the water absorbent resin and theplant powder together in the present invention may be a conventionalone, and examples thereof include cylinder type mixers, screw typemixers, screw type extruders, turbilizers, Nauta type mixers,V-character-shaped mixers, ribbon type mixers, twin-arm kneaders,fluidizing type mixers, air blow type (pneumatic type) mixers, rotarydisk type mixers, roll mixers, and tumbling type mixers. The mixingspeed may be either high or low.

Various inorganic powders may be added further to the above waterabsorbent resin and/or particulate water-absorbing composition. Specificexamples of the inorganic powder include: metal oxides such as silicondioxide and titanium oxide; silicic acid (or its salts) such as naturalzeolite and synthetic zeolite; kaolin; talc; clay; and bentonite. Amongthese, favorable ones are silicon dioxide and silicic acid (or itssalts), and more favorable ones are silicon dioxide and silicic acid (orits salts) with an average particle diameter of not larger than 200 μmas measured by the Coulter Counter Method. The amount of the inorganicpowder depends on combinations of the water-absorbent resin and/orparticulate water-absorbing composition with the inorganic powder, butis in the range of 0.001 to 10 weight parts, favorably 0.01 to 5 weightparts, per 100 weight parts of the water absorbent resin and/orparticulate water-absorbing composition. The method for mixing thewater-absorbent resin and/or particulate water-absorbing compositionwith the inorganic powder is not especially limited, and, for example,dry blend methods in which powders are mixed together or wet mixingmethods are available, but the dry blend methods are preferable.

Incidentally, a difference between the plant powder and a powder onwhich an essence extracted from a plant (essential oil) is carried is asfollows: components having the deodorizing effect are retained infibrous portions of the plant powder, and liquids such as urine preventthe deodorizing components from volatilizing and/or flowing out, and thedeodorizing components effectively work as the need arises, and further,fibrous portions of plants seem to also have an effect on such asadsorption of malodorous components.

In addition, another difference between the plant powder and the powderon which the essence extracted from a plant (essential oil) is carriedis as follows: the latter has a great powder odor strength and thereforedisplays a high deodorizing effect during the practical use, but thisdeodorizing effect is mainly from an odor-masking effect. Thedeodorization by masking is not suitable, because it involves smellspeculiar to the masking material, and because there are differencesbetween individuals' tastes for smells.

The powder odor strength is favorably not more than 4, more favorablynot more than 3, still more favorably not more than 2, most favorablynot more than 1.

The particulate water-absorbing composition as obtained by the aboveproduction process is a particulate water-absorbing composition whichcomprises a plant powder and a water-absorbent resin, wherein thewater-absorbent resin is the specific water-absorbent resin, namely, thewater-absorbent resin of which a surface portion and/or its vicinity istreated by crosslinking with a crosslinking agent reactable with afunctional group of the water-absorbent resin, and/or which exhibits anabsorption capacity of 25 to 60 g/g, a suction power of not less than 9g/g under a load, and an absorption rate of not more than 60 seconds.

A particulate water-absorbing composition, according to the presentinvention, is characterized by comprising a plant powder and awater-absorbent resin, wherein the water-absorbent resin is the specificwater-absorbent resin, namely, the water-absorbent resin of which asurface portion and/or its vicinity is treated by crosslinking with acrosslinking agent reactable with a functional group of thewater-absorbent resin, and/or which exhibits an absorption capacity of25 to 60 g/g, a suction power of not less than 9 g/g under a load, andan absorption rate of not more than 60 seconds, and wherein theparticulate water-absorbing composition exhibits an offensive-odorremoval index of not less than 180 wherein the offensive-odor removalindex is represented by the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

As is mentioned below, the offensive-odor removal index is an index ascalculated from the three removal ratios: hydrogen sulfide removalratio, methylmercaptan removal ratio, and ammonia removal ratio; and itis needed for the particulate water-absorbing composition according tothe present invention that this offensive-odor removal index is not lessthan 180.

JP-A-079159/2000 and JP-A-116829/1999 disclose the malodorous-substanceremovability of water-absorbent resins and their deodorizing effectduring their practical use. As to JP-A-079159/2000, ammonia is used asthe malodorous substance, but, actually, malodorous components ofliquids (e.g. urine, menstrual blood) as excreted out of bodies are sovarious that it does not follow that the ammonia removability copes withall odors. In addition, as to JP-A-116829/1999, the deodorizing effectof water-absorbent resins is examined in a liquid-unabsorbed (unswollen)state by using ammonia, methylamine, and t-butylmercaptan as themalodorous substances to measure their concentrations remaining after apredetermined time has passed, and further the deodorizing effect ofwater-absorbent resins is further examined by using human urine as anevaluation close to a practical state of the use of absorbent articlesto measure the concentrations of gases of ammonia, methylamine, hydrogensulfide, and methylmercaptan after a predetermined time has passed.However, the removal effect on these malodorous components is differentfrom the human sense of smell and, therefore, even if the offensiveodors are much removed, there cannot be said to be the effect in casesof the practical use.

In addition, as to the measurement of the removal of already knownmalodorous substances, the results thereof are much different accordingto measurement conditions such as concentrations of the malodoroussubstances, time passing until the measurement, temperature in a periodof until the measurement, and amounts of water-absorbent resins as used.

Thus, the present inventors diligently studied about water-absorbentresins having the deodorizing effect during the practical use. As aresult, it is not until by the present inventors that the particulatewater-absorbing composition comprising the water-absorbent resin and theplant powder and displaying the offensive-odor removability (hereinreferred to as offensive-odor removal index) under specific conditionshas been found out to display the effect also during the practical use,wherein the water-absorbent resin is the specific water-absorbent resin,namely, the water-absorbent resin of which a surface portion and/or itsvicinity is treated by crosslinking with a crosslinking agent reactablewith a functional group of the water-absorbent resin, and/or whichexhibits an absorption capacity of 25 to 60 g/g, a suction power of notless than 9 g/g under a load, and an absorption rate of not more than 60seconds.

The offensive-odor removal index is an total expression of the ratios ofremovals of ammonia, methylmercaptan, and hydrogen sulfide as themalodorous components by the above particulate water-absorbingcomposition under specific conditions and is represented by thefollowing relational formula:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

Thus, it is not until by setting the degree of importance upon theratios of removals of the malodorous components by the particulatewater-absorbing composition comprising the water-absorbent resin and theplant powder that it has become possible to quantify the human sense ofsmell to offensive odors.

However, the above relational formula according to the present inventionis related only to the particulate water-absorbing compositioncomprising the water-absorbent resin and the plant powder, and it is notuntil by the present inventors that the particulate water-absorbingcomposition has been found out to display the effect during thepractical use in the case where the offensive-odor removal index of thiscomposition is not less than 180.

Incidentally, in general, particulate water-absorbing compositions whichsatisfy the offensive-odor removal index of not less than 180 do notnecessarily display the effect upon liquids (e.g. urine, menstrualblood) as excreted out of bodies. The reason for this can be consideredto be that the offensive-odor removability (removability upon variousmalodorous components contained in liquids as excreted out of bodies),during the practical use, of the particulate water-absorbing compositioncomprising the water-absorbent resin and the plant powder can besimulated by the aforementioned relational formula dealing with ammonia,methylmercaptan, and hydrogen sulfide.

The offensive-odor removal index is favorably not less than 200, morefavorably not less than 220, still more favorably not less than 240, yetstill more favorably not less than 260, particularly favorably not lessthan 280. In the case where the offensive-odor removal index is lessthan 180, there are disadvantages in that the effects of the presentinvention cannot sufficiently be displayed.

If the water-absorbent resin and/or the plant powder is selected toenhance the offensive-odor removal index of the particulatewater-absorbing composition, then it is possible to obtain a particulatewater-absorbing composition which displays a still higher deodorizingeffect during the practical use.

The particulate water-absorbing composition, according to the presentinvention, preferably exhibits an absorption capacity of 25 to 60 g/g, asuction index of not less than 14 g/g under a load, and an absorptionrate of not more than 60 seconds.

The above absorption capacity is more favorably not less than 27 g/g,still more favorably not less than 29 g/g, particularly favorably notless than 31 g/g. In the case where the absorption capacity is less than25 g/g, there are disadvantages in that the absorption quantity isinsufficient. In the case where the absorption capacity is more than 60g/g, there are disadvantages in that the gel strength is so weak thatthe gel blocking easily occurs.

The above suction index under a load is a new parameter for measuringthe power for the water-absorbent resin to suck liquids from paper, andis represented by the sum of a value displayed for a liquid absorptiontime of 3 minutes and a value displayed for a liquid absorption time of60 minutes. If this total value is high, the power to suck liquidssurrounding the particulate water-absorbing composition is so great asto serve to enhance the deodorizing effect of the plant powder by takingin liquids (e.g. urine, menstrual blood) which are excreted out ofbodies to emit offensive odors. In addition, such a function providesthe excellent deodorizing effect not only to the particulatewater-absorbing composition, but also to absorbent articles. The suctionindex under a load is more favorably not less than 16 g/g, still morefavorably not less than 18 g/g, particularly favorably not less than 20g/g.

The above absorption rate is more favorably not more than 55 seconds,still more favorably not more than 50 seconds. In the case where theabsorption rate is more than 60 seconds, there are disadvantages in thatthe liquid absorption is slow and that the deodorizing effect is alsodeteriorated.

The above absorption properties, represented by the absorption capacity,the suction index under a load, and the absorption rate, can not onlyenhance the deodorizing function, but also provide actual absorbentarticles with the reduction of leakage, the reduction of the desorption(wet back) quantity, the prevention of a buttock rash, and theenhancement of a dryness feeling.

With regard to the particulate water-absorbing composition according tothe present invention, the weight-average particle diameter is favorablyin the range of 100 to 600 μm, more favorably 200 to 500 μm, and theproportion of particles having particle diameters of smaller than 106 μmis favorably not more than 10 weight %, more favorably not more than 5weight %, still more favorably not more than 3 weight %.

The particulate water-absorbing composition, according to the presentinvention, is favorably used for sanitary materials.

The absorbent article, according to the present invention, comprises anabsorbent layer, a liquid-permeable surface sheet, and aliquid-impermeable back sheet, wherein the absorbent layer includes thepresent invention particulate water-absorbing composition.

As to the absorbent article according to the present invention,favorably the weight ratio of the particulate water-absorbingcomposition as included in the absorbent layer is not less than 0.3.Favorably the weight ratio of the particulate water-absorbingcomposition to the total of hydrophilic fibers and the particulatewater-absorbing composition is not less than 0.3. Such a weight ratio ismore favorably in the range of 0.4 to 1.0, still more favorably 0.5 to0.8.

As to the absorbent article according to the present invention, in thecase where the weight ratio of the particulate water-absorbingcomposition as included in the absorbent layer is less than 0.3, thereare disadvantages in that the amount of the particulate water-absorbingcomposition as used might be too small to sufficiently provide thedeodorizability to the whole diaper.

The water-absorbent resin which is a component of the particulatewater-absorbing composition as included in the absorbent layer of theabsorbent article according to the present invention comprises acrosslinked poly(acrylic acid (salt)) as the main component.

The particulate water-absorbing composition as included in the absorbentlayer of the absorbent article according to the present invention is aparticulate water-absorbing composition according to the presentinvention, and is therefore characterized by exhibiting anoffensive-odor removal index of not less than 180 which is representedby the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

Furthermore, the particulate water-absorbing composition, as included inthe absorbent layer of the absorbent article according to the presentinvention, favorably exhibits an absorption capacity of 25 to 60 g/g, asuction index of not less than 14 g/g under a load, and an absorptionrate of not more than 60 seconds, wherein the absorption capacity ismore favorably not less than 27 g/g, still more favorably not less than29 g/g, particularly favorably not less than 31 g/g, and wherein thesuction index under a load is more favorably not less than 16 g/g, stillmore favorably not less than 18 g/g, particularly favorably not lessthan 20 g/g, and wherein the absorption rate is more favorably not morethan 55 seconds, still more favorably not more than 50 seconds.

Furthermore, the particulate water-absorbing composition, as included inthe absorbent layer of the absorbent article according to the presentinvention, favorably exhibits a color-difference (L, a, b) in which: Lis not less than 40; the absolute value of a is not more than 6; and bis in the range of 0 to 15; wherein L is more favorably not less than50; still more favorably not less than 60, and wherein the absolutevalue of a is more favorably not more than 5; still more favorably notmore than 4, and wherein b is more favorably in the range of 0 to 14;still more favorably 0 to 13. A color-difference deviating from theabove ranges has the disadvantage of being recognized as a foreignsubstance by consumers in the case of being used for diapers.

As to the absorbent article according to the present invention, theabove modes are favorable, but one of particularly favorable modes is anabsorbent article which comprises an absorbent layer, a liquid-permeablesurface sheet, and a liquid-impermeable back sheet, wherein theabsorbent layer includes an absorbent structure such that the weightratio of the particulate water-absorbing composition to the total ofhydrophilic fibers and the particulate water-absorbing composition isnot less than 0.3, and which is characterized in that the particulatewater-absorbing composition includes a water-absorbent resin comprisinga crosslinked poly(acrylic acid (salt)) as the main component and hasthe following properties:

an offensive-odor removal index of not less than 180;

a suction index of not less than 14 under a load;

a color-difference (L, a, b) in which: L is not less than 40; theabsolute value of a is not more than 6; and b is in the range of 0 to15;

an absorption capacity of 25 to 60 g/g; and

an absorption rate of not more than 60 seconds.

In a process for producing this absorbent article, for example, theparticulate water-absorbing composition is blended or sandwiched with afibrous material to prepare an absorbent layer (absorbent core), and theresultant absorbent core is sandwiched between a liquid-permeable basematerial (surface sheet) and a liquid-impermeable base material (backsheet), and the resultant product is, if necessary, provided withmaterials such as an elastic member, a diffusion layer, or a pressuresensitive adhesive tape, thus obtaining an absorbent article,particularly, a disposable diaper for adults or a sanitary napkin. Theabove absorbent core is, for example, subjected to compression formingso as to have a density of 0.06 to 0.50 g/cc and a basis weight of 0.01to 0.20 g/cm². Incidentally, examples of usable fibrous materialsinclude hydrophilic fibers such as pulverized wood pulp, and otherexamples include cotton linters, crosslinked cellulose fibers, rayon,wadding, wool, acetate, and vinylon. Preferably, they may be air-laid.

Favorable examples of the above hydrophilic fibers include mechanicallypulverized wood pulp, chemical pulp, kraft pulp, cotton, rayon, wadding,wool, acetate, vinylon, polyolefin fibers, and polyester fibers. Thesefibers may be used either alone respectively or in combination with eachother so as to have such as laminate structures or core-sheathstructures. Of the above fibers, those of which the surfaces arehydrophobic are subjected to hydrophilization treatment before beingused.

In addition, hydrophilic fibers which are obtained from plants arefibrous, not powdery. It is generally a fine-thread-shaped substancethat is referred to as “fibrous”, and such a substance favorably has anaspect ratio value larger than the aspect ratio range of the plant fiberas referred to in the present invention. The aspect ratio is a value ascalculated from the following equation: aspect ratio=length/breadthwherein the length and the breadth are those of the hydrophilic fiber.

As is aforementioned, the particulate water-absorbing compositionaccording to the present invention can provide the deodorizing functionto absorbent articles and exhibits excellent deodorizability andexcellent absorption properties for a long time. Specific examples ofsuch absorbent articles include sanitary materials such as disposablediapers for adults, which greatly develop in recent years, diapers forchildren, sanitary napkins, and so-called incontinent pads, but there isno especial limitation thereto. The particulate water-absorbingcomposition, as included in the absorbent article, has very excellentdeodorizability and gel stability, and the absorbent article displayslittle desorption (wet back) and therefore gives a great drynessfeeling, whereby the burden on wearers of the absorbent article or onpeople who take care of the wearers can greatly be lessened.

In addition, the absorbent structure, according to the presentinvention, comprises a hydrophilic fiber, a plant powder, and awater-absorbent resin; and is characterized by exhibiting anoffensive-odor removal index of not less than 180 as a particulatewater-absorbing composition including a mixture of the plant powder andthe water-absorbent resin, wherein the offensive-odor removal index isrepresented by the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

The above wording “as a particulate water-absorbing compositionincluding a mixture of the plant powder and the water-absorbent resin”means “as a particulate water-absorbing composition which is obtained inthe case where the plant powder and the water-absorbent resin are mixedtogether in a weight ratio appropriate to the use for the absorbentstructure”.

As to the absorbent structure according to the present invention, theplant powder and the water-absorbent resin may separately be put intothe absorbent structure. The absorbent structure, according to thepresent invention, favorably comprises the particulate water-absorbingcomposition in which the plant powder is held by the water-absorbentresin. Namely, it favorable that at least parts of the plant powder andthe water-absorbent resin, which are included in the absorbentstructure, are in the form where the plant powder is held by thewater-absorbent resin.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic section of a measurement apparatus as used formeasuring the suction power under a load, which is one of the propertiesas displayed by water-absorbent resins.

In FIG. 1, the symbol “1” represents a container, and the symbol “2”represents a filter paper, and the symbol “3” represents a measurementsection, and the symbol “4” represents an artificial urine, and thesymbol “5” represents a supporting cylinder, and the symbol “6”represents a metal gauze, and the symbol “7” represents a weight.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention is more specifically illustrated bythe following examples of some preferred embodiments in comparison withcomparative examples not according to the invention. However the presentinvention is not limited to these examples. Incidentally, the variousproperties of water-absorbent resins and the volume-average particlediameter of plant powders were measured according to the followingmethods.

(a) Absorption Capacity

To a bag (60 mm×60 mm) made by nonwoven fabric, 0.2 g of water-absorbentresin (or particulate water-absorbing composition) was uniformly added,and then immersed in 100 g of aqueous sodium chloride solution of 0.9weight % (physiological saline) of which the temperature had beenadjusted to 25° C. The bag was pulled up after 60 minutes, and theweight (W2 (g)) of the bag was measured after removing water with acentrifugal separator (250 G) for 3 minutes. In addition, the sameprocedure was carried out without using the water-absorbent resin, andthe resultant weight (W1 (g)) of the bag was measured. Then, theabsorption capacity (g/g) of the water-absorbent resin was calculatedfrom these weights W1 and W2 in accordance with the following equation:water absorption capacity (g/g)=(weight W2 (g)−weight W1 (g))/0.2 (g).

(b) Suction Power Under Load and Suction Index Under Load

First of all, the measurement apparatus as used for measuring thesuction power under a load is hereinafter shortly explained whilereferring to FIG. 1.

As is shown in FIG. 1, the measurement apparatus comprises: a receptacle1; filter paper 2 (No. 2, produced by Advantech, diameter=90 mm, tenpieces); and a measurement part 3.

The receptacle 1 contains 25 g of artificial urine 4 (of which thecomposition is as follows: 97.1 g of deionized water, 1.9 g of urea, 0.8g of sodium chloride, 0.1 g of magnesium chloride hexahydrate, and 0.1 gof calcium chloride) wherein the temperature of the artificial urine isadjusted to 25° C.

The measurement part 3 has a supporting cylinder 5, a wire net 6, and aweight 7 wherein the wire net 6 is attached at the bottom of thesupporting cylinder 5. Then, the measurement part 3 is formed bymounting the supporting cylinder 5 (namely, the wire net 6) on thefilter paper 2 in this order, and further mounting the weight 7 insidethe supporting cylinder 5, namely, on the wire net 6. The inner diameterof the supporting cylinder 5 is formed in 60 mm. The wire net 6 is madeof stainless steel and formed in 400 mesh (mesh opening size: 38 μm).The total weight of the supporting cylinder 5 and the wire net 6 isadjusted to 62 g. Then, an arrangement is made such that a predeterminedamount of water-absorbent resin (or particulate water-absorbingcomposition) can uniformly be spread on the wire net 6. The weight 7 isadjusted in weight such that a load of 1.96 kPa can uniformly be appliedto the wire net 6, in other words, to the water-absorbent resin.

The suction power under a load and the suction index under a load weremeasured with the measurement apparatus having the above-mentionedconstitution. The measurement methods are hereinafter explained.

(1) Suction Power Under Load

First of all, the filter paper 2 was mounted on the receptacle 1. Next,25 g of the artificial urine 4 of which the temperature has beenadjusted to 25° C. is added thereto so that the filter paper 2 willabsorb it. On the other hand, in parallel with this mounting operation,1.0 g of water-absorbent resin (or particulate water-absorbingcomposition) was uniformly spread inside the supporting cylinder 5,namely, on the wire net 6, and the weight 7 was put on thiswater-absorbent resin. Then, the weight of the supporting cylinder 5including the water-absorbent resin and the weight 7 was measured (asweight W1).

Next, the above supporting cylinder 5 (on which the water-absorbentresin and the weight 7 had been mounted) was mounted on the center ofthe filter paper 2. Then, the artificial urine got sucked over a periodof 60 minutes since the supporting cylinder 5 had been mounted on thefilter paper 2. After 60 minutes, the weight of the supporting cylinder5 including the water-absorbent resin (which had sucked the artificialurine) and the weight 7 was measured (as weight W2). Then, how large thesuction power (g/g) under a load was after 60 minutes from the beginningof the absorption was calculated from these weights W1 and W2 inaccordance with the following equation:suction power (g/g) under load=(weight W2 (g)−weight W1 (g))/1.0 (g).

(2) Initial Suction Power Under Load

In the measurement of the suction power under a load as determined inthe above way (1), the same operation was carried out except that theoperation of sucking the artificial urine over a period of 60 minuteswas changed to that over a period of 3 minutes. Specifically, theartificial urine got sucked over a period of 3 minutes, and the weightof the supporting cylinder 5 including the water-absorbent resin (whichhad sucked the artificial urine) and the weight 7 was measured (asweight W3) after 3 minutes. Then, how large the initial suction power(g/g) under a load was after 3 minutes from the beginning of theabsorption was calculated from the following equation:initial suction power (g/g) under load=(weight W3 (g) weight W1(g))/10.0 (g).

(3) Suction Index Under Load

The suction index (g/g) under a load was calculated from the suctionpower under a load and the initial suction power under a load ascalculated in the above ways (1) and (2) in accordance with thefollowing equation:suction index (g/g) under a load=initial suction power (g/g) underload+suction power (g/g) under load.

(c) Absorption Rate

A beaker of 100 ml in capacity (described in GENERAL CATALOGUE A-7000published by Sougo Rikagaku Glass Seisakusho Co., Ltd.; TOP beaker, CAT.No. 501, according to JIS R-3503; and body diameter×height=55 (mm)×70(mm)) is beforehand charged with 50 g of physiological salt solution(its composition was shown below) and a white stirring rod (Teflon(trademark); General catalogue 20,000^(th) edition, published by FlonIndustry Co., Ltd.; Teflon (trademark) stirring rod SA model; ProductNumber: SA-40; and full length 40 mm×diameter 8 mm), wherein thephysiological salt solution has beforehand been colored blue and itstemperature has beforehand been adjusted to 30° C. Then, they arestirred with a magnetic stirrer at a speed of 600 rpm. When 2.0 g ofwater-absorbent resin (or particulate water-absorbing composition) isadded thereto, the gelation of the test liquid is promoted, and the eddytends toward decrease, and then the test liquid gets into a state ofcovering the stirring rod. How long time (seconds) was needed from theaddition of the sample till the covering of the stirring rod with thetest liquid (till the eddy was about to disappear and the rotatingstirring rod as initially seen became unseen by the rise of the eddy)was measured and defined as the absorption rate.

The composition of the physiological salt solution as colored blue isshown below:

Deionized water 991 parts by weight Sodium chloride 9 parts by weightFood additive, namely, Food blue #1 0.02 part by weight(Food additive, namely, Food blue #1: disodiumbenzyl-ethyl-[4′-(4″-(benzylethylamino)-diphenylmethylene)-2′,5-cyclohexadienyliden]-ammonium-2′″,3,3′″-trisulfonate;brilliant blue-FCF; CI No. 42090; and CI Food blue 2)

(d) Color-Difference

With an SZ-Σ 80 model COLOR MEASURING SYSTEM (produced by NipponDenshoku Kogyo Co., Ltd.) being used, the color of the water-absorbentresin (or the particulate water-absorbing composition) was measuredafter XYZ values were corrected on the basis of a standard white board.Then, L, a, b values were determined and defined as thecolor-difference.

(e) Weight-Average Particle Diameter of Water-Absorbent Resin (andParticulate Water-Absorbing Composition)

Ten grams of water-absorbent resin (and particulate water-absorbingcomposition) was classified by shaking it with a sieve shaker (IIDASIEVE SHAKER ES-65 model produced by IIDA SEISAKUSHO CO., LTD.)including JIS standard sieves having an inner diameter of 75 mm (850 μm,600 μm, 300 μm, 150 μm, and 106 μm) for 5 minutes. Then, there weremeasured the weights of the following resultant products as classifiedinto their respective particle diameter ranges: 850-μm-on product, 850to 600 μm, 600 to 300 μm, 300 to 150 μm, 150 to 106 μm, 106-μm-passedproducts as derived from the above sieves respectively. In addition, theparticle diameter distribution of the above-determined particlediameters was plotted on logarithmic probability paper to determine theweight-average particle diameter (D50).

(f) Particle Size of Plant Powder

Ten grams of plant powder was shaken with a sieve shaker (IIDA SIEVESHAKER ES-65 model produced by IIDA SEISAKUSHO CO., LTD.) fitlyincluding JIS standard sieves having an inner diameter of 75 mm (850 μm,600 μm, 500 μm, 300 μm, 150 μm, 106 μm, 75 μm, and 45 μm) for 5 minutesunder the conditions such as room temperature of 25° C. and relativehumidity of 25%. Thus, the particle size of the plant powder wasexamined.

(g) Water Content of Plant Powder

An aluminum cup (described in GENERAL CATALOGUE A-7000 published bySougo Rikagaku Glass Seisakusho Co., Ltd.; Aluminum cup, Form: 107;volume=60 ml; and upper diameter×lower diameter×height=65 (mm)×53(mm)×23 (mm)) was uniformly charged with 1.0 g of plant powder. Theweight W (g) was measured after the plant powder was dried with a dryer(NATURAL OVEN NDO-450 produced by TOKYO RIKAKIKAI CO., LTD.) at 105° C.for 3 hours. Then, the water content (%) of the plant powder wascalculated from this weight W in accordance with the following equation:water content (%)=(1.0 (g)−W (g))×100.

(h) Powder Odor Strength

A polypropylene cup of 120 ml in capacity having a cover (produced byTeraoka; Pack-Ace; opening diameter (mm)×bottom diameter (mm)×height(mm)=58×54×74) was charged with 2.0 g of water-absorbent resin (orparticulate water-absorbing composition), and this receptacle wascovered and then kept at 25° C. The cover was opened after one hour, andthen the odor strength was judged by twenty adult panelists' taking asmell about 3 cm apart from the top of the cup.

Each panelist recorded a score according to the following six-rankjudgment standard, and then the average thereof was calculated.

0: (Odorless); 1: (very faint); 2: (faint); 3: (easily felt); 4:(strong); 5: (very strong)

(i) Deodorizing Test (Water-Absorbent Resin or ParticulateWater-Absorbing Composition)

An amount of 50 ml was picked from a human urine mixture as a collectionfrom 10 adults and then placed into a polypropylene cup of 120 ml incapacity having a cover (produced by Teraoka; Pack-Ace; opening diameter(mm)×bottom diameter (mm)×height (mm)=58×54×74). Then, a swollen gel wasformed by adding 2.0 g of water-absorbent resin (or particulatewater-absorbing composition) thereto. The human urine was used within 2hours after having been excreted. This receptacle was covered, and thenthe swollen gel was kept at 37° C. The cover was opened after 1 minute(initial stage), 3 hours, and 6 hours from the end of the liquidabsorption, and then the deodorizing effect was judged by twenty adultpanelists' taking a smell about 3 cm apart from the top of the cup.

Each panelist recorded a score according to the following five-rankjudgment standard, and then the average thereof was calculated.Incidentally, what was obtained in the same way as above except to addonly the human urine without adding the water-absorbent resin (orparticulate water-absorbing composition) was defined as a standardsample, and its odor was judged 5 to evaluate the deodorizing effect.

1: (No odor); 2: (odor which is hardly on one's mind); 3: (odor which isperceivable but allowable); 4: (strong odor); 5: (intense odor)

(j) Gel Stability

In a polypropylene cup of 120 ml in capacity having a cover (produced byTeraoka; Pack-Ace; opening diameter (mm)×bottom diameter (mm)×height(mm)=58×54×74), 1 g of water-absorbent resin (or particulatewater-absorbing composition) was swollen with 25 ml of artificial urineincluding L-ascorbic acid in a concentration of 0.005 weight %. Thisreceptacle was covered and then left alone at 37° C. for 16 hours.Thereafter, the gel stability was estimated by the feel of the gel.

The gel stability was estimated according to the following judgmentstandard. ◯: (The gel is firm); Δ: (The gel is softened); and X: (Thegel is entirely collapsed).

The composition of the artificial urine is mentioned below. Deionizedwater 97.1 g Urea  1.9 g Sodium chloride  0.8 g Magnesium sulfate  0.1 gCalcium chloride  0.1 g

(k) Offensive-Odor Removal Index

(l) Hydrogen Sulfide Removal Ratio

A stoppable Erlenmeyer flask of 200 ml in capacity (described in GENERALCATALOGUE A-7000 published by Sougo Rikagaku Glass Seisakusho Co., Ltd.;TOP Erlenmeyer flask, CAT. No. 506 according to JIS R-3503; and maximumdiameter×height=81 (mm)×131 (mm)) was charged with 50 g of aqueoussodium chloride solution of 0.9 weight % (physiological saline) and 10.0g of water-absorbent resin (or particulate water-absorbing composition)to uniformly swell it. After this Erlenmeyer flask was stopped up with asilicone rubber stopper, a predetermined amount of standard gas wasinjected through the silicone rubber stopper using a syringe having aneedle, and then the flask was left alone at 25° C. After 3 hours, 1 mlof head-space gas was collected through the silicone rubber stopperusing a syringe having a needle, and the gas concentration C2 (ppm) wasmeasured by gas chromatography ((Analytical conditions:Instrument=GC-14A produced by Shimadzu Corporation; Detector=FPD; Columntemperature=70° C.; Carrier gas=N₂; Carrier flow rate=30 ml/min),(Column as used: Manufactory=Shinwa Kako Co., Ltd.; Liquidphase=1,2,3-tris(2-cyanoethoxy)propane 25%; Carrier=ShimalaiteAW-DMCS-ST 80 to 100 mesh; Size of column=Φ3 mm×3 M)). In addition, thesame procedure was carried out without using either the aqueous sodiumchloride solution of 0.9 weight % or the water-absorbent resin (orparticulate water-absorbing composition), and then the resultant gasconcentration C1(ppm) was measured. Then, the hydrogen sulfide removalratio (%) was calculated from these concentrations C1 and C2 inaccordance with the following equation:Removal ratio (%)=(gas concentration C1−gas concentration C2)/gasconcentration C1×100

The measurement was carried out three times per one kind of thewater-absorbent resin (or particulate water-absorbing composition), andthen its average value was calculated.

The concentration of the standard gas as used and the amount thereof asinjected are mentioned below.

Concentration: Hydrogen sulfide 6,110 ppm/N₂ Balance

Amount as injected: 0.82 ml

In addition, the method for preparing a calibration curve in measuringthe gas concentration is mentioned below.

Gas having concentrations of 1, 3, 10, and 20 ppm respectively wereprepared by using the standard gas (hydrogen sulfide 6,110 ppm/N₂balance), and 1 ml thereof was analyzed by gas chromatography, and thenthe peak area was measured.

The resultant peak area and the gas concentration (ppm) were regarded asX value and Y value respectively, and these values were plotted on abi-logarithmic graph to prepare the calibration curve.

(2) Methylmercaptan Removal Ratio

A stoppable Erlenmeyer flask of 200 ml in capacity (described in GENERALCATALOGUE A-7000 published by Sougo Rikagaku Glass Seisakusho Co., Ltd.;TOP Erlenmeyer flask, CAT. No. 506 according to JIS R-3503; and maximumdiameter×height=81 (mm)×131 (mm)) was charged with 50 g of aqueoussodium chloride solution of 0.9 weight % (physiological saline) and 10.0g of water-absorbent resin (or particulate water-absorbing composition)to uniformly swell it. After this Erlenmeyer flask was stopped up with asilicone rubber stopper, a predetermined amount of standard gas wasinjected through the silicone rubber stopper using a syringe having aneedle, and then the flask was left alone at 25° C. After 3 hours, 1 mlof head-space gas was collected through the silicone rubber stopperusing a syringe having a needle, and the gas concentration C4 (ppm) wasmeasured by gas chromatography ((Analytical conditions:Instrument=GC-14A produced by Shimadzu Corporation; Detector=FPD; Columntemperature=70° C.; Carrier gas=N₂; Carrier flow rate=30 ml/min),(Column as used: Manufactory=Shinwa Kako Co., Ltd.; Liquidphase=1,2,3-tris(2-cyanoethoxy)propane 25%; Carrier=ShimalaiteAW-DMCS-ST 80 to 100 mesh; Size of column=Φ3 mm×3 M)). In addition, thesame procedure was carried out without using either the aqueous sodiumchloride solution of 0.9 weight % or the water-absorbent resin (orparticulate water-absorbing composition), and then the resultant gasconcentration C3 (ppm) was measured. Then, the methylmercaptan removalratio (%) was calculated from these concentrations C3 and C4 inaccordance with the following equation:Removal ratio (%)=(gas concentration C3−gas concentration C4)/gasconcentration C3×100

The measurement was carried out three times per one kind of thewater-absorbent resin (or particulate water-absorbing composition), andthen its average value was calculated.

The concentration of the standard gas as used and the amount thereof asinjected are mentioned below.

Concentration: Methylmercaptan 5,960 ppm/N₂ Balance

Amount as injected: 0.84 ml

In addition, the method for preparing a calibration curve in measuringthe gas concentration is mentioned below.

Gas having concentrations of 1, 3, 10, and 20 ppm respectively wereprepared by using the standard gas (methylmercaptan 5,960 ppm/N₂balance), and 1 ml thereof was analyzed by gas chromatography, and thenthe peak area was measured.

The resultant peak area and the gas concentration (ppm) were regarded asX value and Y value respectively, and these values were plotted on abi-logarithmic graph to prepare the calibration curve.

(3) Ammonia Removal Ratio

A smelling bag of 3 L in capacity (produced by Ohmi Odor Air ServiceCo., Ltd.) was charged with 10.0 g of water-absorbent resin (orparticulate water-absorbing composition) and 50 g of mixed liquid(comprising aqueous ammonia solution of 29% and aqueous sodium chloridesolution of 0.9 weight % in a weight ratio of 1:49) to uniformly swellthe water-absorbent resin (or particulate water-absorbing composition).Three liters of odorless air was injected into this smelling bag, and itwas left alone at 25° C. after it was stopped up with a silicone rubberstopper. After 3 hours, the silicone rubber stopper was removed, and thecontamination by the air outside was inhibited, and then the atmosphericconcentration C6 inside the bag was measured with a gas sampler (GV-100Sproduced by Gastech Co., Ltd.) and a gastic reactotube (No. 3HM, No. 3M,No. 3L produced by Gastech Co., Ltd.). In addition, the same procedurewas carried out without using the water-absorbent resin (or particulatewater-absorbing composition), and then the resultant atmosphericconcentration C5 was measured. Then, the ammonia removal ratio (%) wascalculated from these concentrations C5 and C6 in accordance with thefollowing equation:Removal ratio (%)=(gas concentration C5−gas concentration C6)/gasconcentration C5×100

The measurement was carried out three times per one kind of thewater-absorbent resin (or particulate water-absorbing composition), andthen its average value was calculated.

(4) Offensive-Odor Removal Index

The offensive-odor removal index was calculated by applying the hydrogensulfide removal ratio, the methylmercaptan removal ratio, and theammonia removal ratio, as obtained in the above ways (1), (2) and (3),to the following equation:Offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.

(l) Evaluation of Absorption Properties of Absorbent Article (AbsorptionRate and Substantial Absorption Quantity)

Fifty parts by weight of non-powdery fibrous wood pulp and 50 parts byweight of particulate water-absorbing composition were blended togetherin a dry manner with a mixer. Next, the resultant blend waspneumatically molded on a wire screen of 400 mesh (mesh opening size=38μm) with a batch-type pneumatic molding apparatus, thereby forming a webhaving a size of 120 mm×400 mm. Furthermore, this web was pressed undera pressure of 196.14 kPa for 5 seconds, thus obtaining an absorbentstructure having a basis weight of about 0.047 g/cm².

Subsequently, a back sheet (liquid-impermeable sheet) (comprisingliquid-impermeable polypropylene and having what is called a leggather), the above-mentioned absorbent structure, and a top sheet(liquid-impermeable sheet) (comprising liquid-permeable polypropylene)were stuck on each other in this order with a double-coated tape, thusobtaining an absorbent article (namely, an incontinent pad for adults).The weight of this absorbent article was 44 g.

Next, the absorbent article was spread, and thereon a 20-mesh metalgauze having a size of 140 mm×500 mm was mounted. Furthermore thereon anapparatus for measuring the properties of absorbent article under aload, which had a size of 150 mm×400 mm and a weight of 22,000 g in alland was provided with a cylinder of the diameter of 70 mm and the heightof 80 mm in the central portion of the apparatus, was mounted betweenthe right and left leg gathers so that the central portion of thecylinder would conform to the center of the absorbent article. Throughthe cylindrical portion, 150 g of artificial urine (composition: anaqueous solution having a urea content of 1.9 weight %, an NaCl contentof 0.8 weight %, a calcium chloride content of 0.1 weight %, and amagnesium sulfate content of 0.1 weight %), of which the temperature hadbeen adjusted to 37° C., was poured all at once. Thereafter, they wereleft alone for 1 hour, and further 150 g of the artificial urine waspoured thereonto all at once. The time passing until the artificialurine was completely absorbed from the top sheet of the absorbentarticle was observed from above to measure the absorption rate(seconds).

They were left alone for 1 hour after the artificial urine had beenpoured thereonto for the second time. Thereafter, the apparatus formeasuring the properties of the absorbent article under a load and the20-mesh metal gauze were removed from the absorbent article, and thenthereon a paper towel (produced by Oji Seishi Co., Ltd.; Kitchen TowelExtra Dry; 30-ply as cut into the size of 120 mm×450 mm) was mounted,and then thereto a load of 37 g/cm² (3.63 kPa) was applied for 1 minuteto measure the quantity W1 of the liquid returning to the paper towel.In addition, the artificial urine which was not absorbed by theabsorbent article but leaked out along the leg gather in a period of 2hours after the artificial urine had been poured for the first time (inother words, until the amount of the liquid returning to the paper towelwas measured) was absorbed by a paper towel (Kitchen Towel Extra Dryproduced by Oji Seishi Co., Ltd.) to measure the quantity W2 of theliquid as leaked out.

Then, the substantial absorption quantity (g) as absorbed by theabsorbent article was calculated from these liquid quantities W1 and W2in accordance with the following equation:Substantial absorption quantity (g)=300 (g)−(W1 (g)+W2 (g))

(m) Evaluation of Absorption Properties of Absorbent Article(Deodorizing Test)

Fifty parts by weight of non-powdery fibrous wood pulp and 50 parts byweight of particulate water-absorbing composition were blended togetherin a dry manner with a mixer. Next, the resultant blend waspneumatically molded on a wire screen of 400 mesh (mesh opening size=38μm) with a batch-type pneumatic molding apparatus, thereby forming a webhaving a size of 120 mm×400 mm. Furthermore, this web was pressed undera pressure of 196.14 kPa for 5 seconds, thus obtaining an absorbentstructure having a basis weight of about 0.047 g/cm².

Subsequently, a back sheet (liquid-impermeable sheet) (comprisingliquid-impermeable polypropylene and having what is called a leggather), the above-mentioned absorbent structure, and a top sheet(liquid-impermeable sheet) (comprising liquid-permeable polypropylene)were stuck on each other in this order with a double-coated tape, andbeside, the resultant stuck product was provided with what is called twotape fasteners, thus obtaining an absorbent article (namely, adisposable diaper). The weight of this absorbent article was 46 g.

The above absorbent articles were put on ten babies (aged 1) as monitorsovernight and then collected the following day. The absorbent structureportion (what is called core portion), comprising the particulatewater-absorbing composition and the non-powdery fibrous wood pulp, wascut into the size of 10×10 cm, and then put into a polypropylene cup of250 ml in capacity having a cover (produced by Teraoka; Pack-Ace;opening diameter (mm)×bottom diameter (mm)×height (mm)=69×63×97). Thisreceptacle was covered and then the temperature of the absorbentstructure portion was kept at 37° C. The cover was opened after onehour, and then the deodorizing effect was judged by twenty adultpanelists' taking a smell about 3 cm apart from the top of the cup.

Each panelist recorded a score according to the following five-rankjudgment standard, and then the average thereof was calculated.

1: (No odor); 2: (odor which is hardly on one's mind); 3: (odor which isperceivable but allowable); 4: (strong odor); 5: (intense odor)

(n) Evaluation of Absorption Properties of Absorbent Article (DrynessFeeling and Deodorizing Effect)

Fifty parts by weight of non-powdery fibrous wood pulp and 50 parts byweight of particulate water-absorbing composition were blended togetherin a dry manner with a mixer. Next, the resultant blend waspneumatically molded on a wire screen of 400 mesh (mesh opening size=38μm) with a batch-type pneumatic molding apparatus, thereby forming a webhaving a size of 120 mm×400 mm. Furthermore, this web was pressed undera pressure of 196.14 kPa for 5 seconds, thus obtaining an absorbentstructure having a basis weight of about 0.047 g/cm².

Subsequently, a back sheet (liquid-impermeable sheet) (comprisingliquid-impermeable polypropylene and having what is called a leggather), the above-mentioned absorbent structure, and a top sheet(liquid-impermeable sheet) (comprising liquid-permeable polypropylene)were stuck on each other in this order with a double-coated tape, thusobtaining an absorbent article (namely, an incontinent pad for adults).The weight of this absorbent article was 44 g.

The above absorbent articles were put on five grown-up men as monitors,who judged a dryness feeling after urination once.

Each man recorded a score according to the following three-rank judgmentstandard, and then the average thereof was calculated.

1: (Non-sticky to the touch); 2: (feeling slightly wet); 3: (so damp andsticky to the touch as to be unpleasant)

Besides, the absorbent structure portion (what is called core portion),comprising the particulate water-absorbing composition and thenon-powdery fibrous wood pulp, was cut into the size of 10×10 cm, andthen put into a polypropylene cup of 250 ml in capacity having a cover(produced by Teraoka; Pack-Ace; opening diameter (mm)×bottom diameter(mm)×height (mm)=69×63×97). This receptacle was covered and then thetemperature of the absorbent structure portion was kept at 37° C. Thecover was opened after 6 hours, and then the deodorizing effect wasjudged by twenty adult panelists' taking a smell about 3 cm apart fromthe top of the cup.

Each panelist recorded a score according to the following five-rankjudgment standard, and then the average thereof was calculated.

1: (No odor); 2: (odor which is hardly on one's mind); 3: (odor which isperceivable but allowable); 4: (strong odor); 5: (intense odor)

(o) Volume-Average Particle Diameter of Plant Powder

The volume-average particle diameter was measured with SALD-3000(produced by Shimadzu Corporation).

The measurement was carried out according to a operation manual asprescribed for the SALD-3000. In addition, the weight of the plantpowder as used for the measurement was in the range where the absorbanceduring the measurement was within the measurement range.

Referential Example 1

A reaction liquid was obtained by dissolving 4.00 g of polyethyleneglycol diacrylate (molar-number-average degree of additionpolymerization of ethylene oxide: 8) into 5,500 g of aqueous sodiumacrylate solution having a neutralization ratio of 75 mol % (monomerconcentration: 33 weight %). Next, this reaction liquid was deaeratedunder a nitrogen gas atmosphere for 30 minutes. Next, the reactionliquid was supplied to a reactor as prepared by lidding a jacketedstainless-steel-made twin-arm kneader of 10 liters in capacity havingtwo sigma type blades, and then the internal air of the system wasdisplaced with nitrogen while the reaction liquid was maintained at 30°C. Subsequently, while the reaction liquid was stirred, 2.46 g of sodiumpersulfate and 0.10 g of L-ascorbic acid were added thereto, with theresult that the reaction started after about 1 minute. Then, thepolymerization was carried out at 30 to 80° C., and the resultanthydrogel polymer was got out after 60 minutes from the start of thepolymerization. The resultant hydrogel polymer was in the form of finelydivided pieces having a diameter of about 5 mm. This finely dividedhydrogel polymer was spread on a metal gauze of 50 mesh (mesh openingsize=300 μm) and then dried with hot air of 150° C. for 90 minutes.Next, the resultant dry material was pulverized with a vibration milland then classified with a metal gauze of 20 mesh (mesh opening size=850μm), thus obtaining an irregularly pulverized water-absorbent resin (a)having a weight-average particle diameter of 295 μm.

A surface-crosslinking agent, comprising 1 part by weight of propyleneglycol, 0.05 part by weight of ethylene glycol diglycidyl ether, 3 partsby weight of water, and 1 part by weight of isopropyl alcohol, wasblended with 100 parts by weight of the resultant water-absorbent resin(a). The resultant mixture was heat-treated at 210° C. for 50 minutes,thus obtaining a water-absorbent resin (1). This water-absorbent resin(1) exhibited an absorption capacity of 33 (g/g), a suction power of 11(g/g) under a load, and a suction index of 21 (g/g) under a load. Inaddition, the weight-average particle diameter of this water-absorbentresin was 295 μm which was not very different from that of the originalwater-absorbent resin.

Referential Example 2

An irregularly pulverized water-absorbent resin (b) having aweight-average particle diameter of 360 μm was obtained in the same wayas of Referential Example 1 except that the monomer concentration of theaqueous sodium acrylate solution having a neutralization ratio of 75 mol% was changed to 38 weight %, and that the crosslinking agent waschanged from polyethylene glycol diacrylate to 7.0 g oftrimethylolpropane triacrylate, and that the pulverization conditions ofthe vibration mill were changed.

A surface-crosslinking agent, comprising 1 part by weight of propyleneglycol, 0.05 part by weight of ethylene glycol diglycidyl ether, 3 partsby weight of water, and 1 part by weight of isopropyl alcohol, wasblended with 100 parts by weight of the resultant water-absorbent resin(b). The resultant mixture was heat-treated at 210° C. for 45 minutes,thus obtaining a water-absorbent resin (2). This water-absorbent resin(2) exhibited an absorption capacity of 27 (g/g), a suction power of 11(g/g) under a load, a suction index of 20 (g/g) under a load, and anabsorption rate of 50 seconds. In addition, the weight-average particlediameter of this water-absorbent resin was 360 μm which was not verydifferent from that of the original water-absorbent resin.

Referential Example 3

The irregularly pulverized water-absorbent resin (b) having aweight-average particle diameter of 360 μm, as obtained in ReferentialExample 2, was regarded as a water-absorbent resin (3), which exhibitedan absorption capacity of 32 (g/g), a suction power of 8 (g/g) under aload, and a suction index of 13 (g/g) under a load.

Referential Example 4

An irregularly pulverized water-absorbent resin (c) having aweight-average particle diameter of 440 μm was obtained in the same wayas of Referential Example 2 except that the pulverization conditions ofthe vibration mill were changed. This water-absorbent resin (c) wasregarded as a water-absorbent resin (4), which exhibited an absorptioncapacity of 32 (g/g), a suction power of 8 (g/g) under a load, and asuction index of 13 (g/g) under a load.

Referential Example 5

The irregularly pulverized water-absorbent resin (a) having aweight-average particle diameter of 295 μm, as obtained in ReferentialExample 1, was regarded as a water-absorbent resin (5), which exhibitedan absorption capacity of 45 (g/g), and a suction index of 9 (g/g) undera load.

Examples 1 to 27

The kinds of the water-absorbent resins and plant powders as used areshown together in Table 1. The properties and the deodorizing effects ofparticulate water-absorbing compositions (1 to 27) are shown together inTables 3 and 4. In addition, some evaluations of the absorptionproperties of absorbent articles (1 to 27) including the particulatewater-absorbing compositions (1 to 27) are shown together in Table 7.

Hereinafter, production processes of the water-absorbing compositions (1to 27) are explained.

Example 1

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.1 part by weight ofpepper (White Pepper Powder produced by Takasago Spice Co., Ltd.; thisWhite Pepper Powder had a water content of 10.3%, and a particlediameter 300 μm-passed product thereof was used, and its volume-averageparticle diameter was 77 μm) as a plant powder by a dry blend method,thus obtaining a particulate water-absorbing composition (1). Theresultant particulate water-absorbing composition (1) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 6 weight%.

Example 2

A particulate water-absorbing composition (2) was obtained in the sameway as of Example 1 except that 0.5 part by weight of the pepper wasblended by a dry blend method. The resultant particulate water-absorbingcomposition (2) had a weight-average particle diameter of 295 μm, inwhich the ratio of particles having particle diameters of smaller than106 μm was 6 weight %.

Example 3

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight ofJapanese pepper (Japanese Pepper Powder produced by Takasago Spice Co.,Ltd.; this Japanese Pepper Powder had a water content of 9.0%, and aparticle diameter 500 μm-passed product thereof was used, and itsvolume-average particle diameter was 172 μm) as a plant powder by a dryblend method, thus obtaining a particulate water-absorbing composition(3). The resultant particulate water-absorbing composition (3) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 6 weight%.

Example 4

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight ofginger (Ginger Powder produced by Takasago Spice Co., Ltd.; this GingerPowder had a water content of 9.1%, and a particle diameter 300μm-passed product thereof was used, and its volume-average particlediameter was 64 μm) as a plant powder and further with 1.0 part byweight of ion-exchanged water. Thereafter, 0.3 part by weight of silicondioxide (Aerosil 200 produced by Nippon Aerosil Co., Ltd.) was added asan inorganic powder, thus obtaining a particulate water-absorbingcomposition (4). The resultant particulate water-absorbing composition(4) had a weight-average particle diameter of 295 μm, in which the ratioof particles having particle diameters of smaller than 106 μm was 5weight %.

Example 5

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 0.5 part by weight ofcapsicum (Red Pepper Powder produced by Takasago Spice Co., Ltd.; thisRed Pepper Powder had a water content of 6.2%, and a particle diameter500 μm-passed product thereof was used, and its volume-average particlediameter was 244 μm) as a plant powder by a dry blend method, thusobtaining a particulate water-absorbing composition (5). The resultantparticulate water-absorbing composition (5) had a weight-averageparticle diameter of 360 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 5 weight %.

Example 6

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 0.5 part by weight ofparsley (Parsley Powder CP produced by Yasuma Co., Ltd.; this ParsleyPowder CP had a water content of 6.7%, and a particle diameter 300μm-passed product thereof was used, and its volume-average particlediameter was 142 μm) as a plant powder by a dry blend method, thusobtaining a particulate water-absorbing composition (6). The resultantparticulate water-absorbing composition (6) had a weight-averageparticle diameter of 360 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 5 weight %.

Example 7

A particulate water-absorbing composition (7) was obtained in the sameway as of Example 6 except that 1.0 part by weight of the parsley wasblended by a dry blend method. The resultant particulate water-absorbingcomposition (7) had a weight-average particle diameter of 360 μm, inwhich the ratio of particles having particle diameters of smaller than106 μm was 5 weight %.

Example 8

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight ofgreen tea (product obtained by pulverizing “green tea (name of rawmaterial) sold by Nishie Corporation (address: 1652-3,Kakiuchikita-machi, Aboshi-ku, Himeji-shi, Hyogo Prefecture, Japan)”with a hammer mill; this pulverized product of green tea had a watercontent of 2.0%, and a particle diameter 850 μm-passed product thereofwas used, and its volume-average particle diameter was 287 μm) as aplant powder by a dry blend method, thus obtaining a particulatewater-absorbing composition (8). The resultant particulatewater-absorbing composition (8) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 6 weight %.

Example 9

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.3 part by weight ofmilled green tea (sold by Itohen Co., Ltd. (address: 3-47-10, Hon-machi,Shibuya-ku, Tokyo Prefecture, Japan), trade name: Milled Green Tea 30 gwith ease, name of raw material: tea; this Milled Green Tea had a watercontent of 3.4%, and a particle diameter 300 μm-passed product thereofwas used, and its volume-average particle diameter was 77 μm) as a plantpowder by a dry blend method, thus obtaining a particulatewater-absorbing composition (9). The resultant particulatewater-absorbing composition (9) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 6 weight %.

Example 10

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight ofgreen tea (product obtained by pulverizing “green tea (name of rawmaterial) sold by Nishie Corporation (address: 1652-3,Kakiuchikita-machi, Aboshi-ku, Himeji-shi, Hyogo Prefecture, Japan)”with a hammer mill; this pulverized product of green tea had a watercontent of 2.4%, and a particle diameter 106 μm-passed product thereofwas used) as a plant powder and further with 2.0 parts by weight ofion-exchanged water, thus obtaining a particulate water-absorbingcomposition (10). The resultant particulate water-absorbing composition(10) had a weight-average particle diameter of 295 μm, in which theratio of particles having particle diameters of smaller than 106 μm was4 weight %.

Example 11

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight ofblack tea (product obtained by pulverizing “Lipton YELLOW LABEL (tradename) sold by Nippon Lever Co., Ltd. (address: 2-22-3, Shibuya,Shibuya-ku, Tokyo Prefecture, Japan)” with a hammer mill; thispulverized product of black tea had a water content of 6.8%, and aparticle diameter 600 μm-passed product thereof was used, and itsvolume-average particle diameter was 285 μm) as a plant powder by a dryblend method, thus obtaining a particulate water-absorbing composition(11). The resultant particulate water-absorbing composition (11) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 6 weight%.

Example 12

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.2 part by weight ofoolong tea (product obtained by pulverizing “Oolong Tea (trade name)produced by Ujien Co., Ltd. (address: 2-22, Mikagenaka-machi 1-chome,Higashinada-ku, Kobe-shi, Hyogo Prefecture, Japan)” with a hammer mill;this pulverized product of oolong tea had a water content of 4.8%, and aparticle diameter 850 μm-passed product thereof was used, and itsvolume-average particle diameter was 290 μm) as a plant powder by a dryblend method, thus obtaining a particulate water-absorbing composition(12). The resultant particulate water-absorbing composition (12) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 6 weight%.

Example 13

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 0.5 part by weight ofPu-erh tea (product obtained by pulverizing “Pu-erh Tea (trade name)sold by Ujinotsuyu Seicha Co., Ltd. (address: 50,Kamikomahigashitsukurimichi, Yamashiro-cho, Soraku-gun, KyotoPrefecture, Japan)” with a hammer mill; this pulverized product ofPu-erh tea had a water content of 7.8%, and a particle diameter 600μm-passed product thereof was used, and its volume-average particlediameter was 256 μm) as a plant powder by a dry blend method, thusobtaining a particulate water-absorbing composition (13). The resultantparticulate water-absorbing composition (13) had a weight-averageparticle diameter of 360 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 5 weight %.

Example 14

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 0.5 part by weight ofa dried product of the residue of extraction from green tea (productobtained by adding 10 g of “green tea (name of raw material) sold byNishie Corporation (address: 1652-3, Kakiuchikita-machi, Aboshi-ku,Himeji-shi, Hyogo Prefecture, Japan)” into 500 g of ion-exchanged waterof about 95° C. to blend them together, and then filtrating theresultant mixture after 5 minutes, and then vacuum-drying thefiltered-off residue (namely, the residue of extraction from green tea)at 60° C., and then pulverizing the dried product with a hammer mill;this pulverized dried product of the residue of extraction from greentea had a water content of 6.3%, and a particle diameter 850 μm-passedproduct thereof was used, and its volume-average particle diameter was346 μm) as a plant powder by a dry blend method, thus obtaining aparticulate water-absorbing composition (14). The resultant particulatewater-absorbing composition (14) had a weight-average particle diameterof 360 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 5 weight %.

Example 15

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 1.0 part by weight ofa dried product of the residue of extraction from black tea (productobtained by adding 10 g of “Lipton YELLOW LABEL (trade name) sold byNippon Lever Co., Ltd. (address: 2-22-3, Shibuya, Shibuya-ku, TokyoPrefecture, Japan)” into 500 g of ion-exchanged water of about 95° C. toblend them together, and then filtrating the resultant mixture after 5minutes, and then vacuum-drying the filtered-off residue (namely, theresidue of extraction from black tea) at 60° C., and then pulverizingthe dried product with a hammer mill; this pulverized dried product ofthe residue of extraction from black tea had a water content of 7.9%,and a particle diameter 850 μm-passed product thereof was used, and itsvolume-average particle diameter was 352 μm) as a plant powder andfurther with 1.0 part by weight of ion-exchanged water and thereafterwith 0.3 part by weight of silicon dioxide (Aerosil 200 produced byNippon Aerosil Co., Ltd.) as an inorganic powder, thus obtaining aparticulate water-absorbing composition (15). The resultant particulatewater-absorbing composition (15) had a weight-average particle diameterof 360 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 4 weight %.

Example 16

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 0.5 part by weight ofa dried product of the residue of extraction from oolong tea (productobtained by adding 10 g of “Oolong Tea (trade name) produced by UjienCo., Ltd. (address: 2-22, Mikagenaka-machi 1-chome, Higashinada-ku,Kobe-shi, Hyogo Prefecture, Japan)” into 500 g of ion-exchanged water ofabout 95° C. to blend them together, and then filtrating the resultantmixture after 5 minutes, and then vacuum-drying the filtered-off residue(namely, the residue of extraction from oolong tea) at 60° C., and thenpulverizing the dried product with a hammer mill; this pulverized driedproduct of the residue of extraction from oolong tea had a water contentof 6.5%, and a particle diameter 600 μm-passed product thereof was used,and its volume-average particle diameter was 297 μm) as a plant powderby a dry blend method, thus obtaining a particulate water-absorbingcomposition (16). The resultant particulate water-absorbing composition(16) had a weight-average particle diameter of 360 μm, in which theratio of particles having particle diameters of smaller than 106 μm was5 weight %.

Example 17

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofcitron (product obtained by pulverizing “Kizami Yuzu (trade name) soldby S&B Foods Co., Ltd. (address: 18-6, Nipponbashi Kabuto-cho, Chuo-ku,Tokyo Prefecture, Japan)” with a hammer mill; this pulverized product ofcitron had a water content of 8.5%, and a particle diameter 850μm-passed product thereof was used) as a plant powder and further with1.0 part by weight of ion-exchanged water, thus obtaining a particulatewater-absorbing composition (17). The resultant particulatewater-absorbing composition (17) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 5 weight %.

Example 18

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight oflime peel (product obtained by peeling a commonly commercially availablelime, and then pulverizing the resultant peel with a mixer, and thenvacuum-drying the pulverized peel at 60° C., and then furtherpulverizing the dried product with a hammer mill; this pulverized driedproduct of lime peel had a water content of 5.6%, and a particlediameter 850 μm-passed product thereof was used) as a plant powder by adry blend method and further with 2.0 parts by weight of ion-exchangedwater, thus obtaining a particulate water-absorbing composition (18).The resultant particulate water-absorbing composition (18) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 4 weight%.

Example 19

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofmandarin orange peel (product obtained by peeling a commonlycommercially available mandarin orange (from Arita, Japan), and thenpulverizing the resultant peel with a mixer, and then vacuum-drying thepulverized peel at 60° C., and then further pulverizing the driedproduct with a hammer mill; this pulverized dried product of mandarinorange peel had a water content of 4.5%, and a particle diameter 850μm-passed product thereof was used) as a plant powder and further with2.0 parts by weight of ion-exchanged water and thereafter with 0.3 partby weight of silicon dioxide (Aerosil 200 produced by Nippon AerosilCo., Ltd.) as an inorganic powder, thus obtaining a particulatewater-absorbing composition (19). The resultant particulatewater-absorbing composition (19) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 4 weight %.

Example 20

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofsea tangle (product obtained by cutting “Hidaka Kizami Wakakombu(product name) produced by Maruzen Naya Shoten (address: 28-1,Shinkawa-cho, Hakodate-shi, Hokkaido Prefecture, Japan)” into as smallpieces as possible with scissors, and then pulverizing the resultantpieces with a hammer mill; this pulverized product of sea tangle had awater content of 9.9%, and a particle diameter 850 μm-passed productthereof was used) as a plant powder and further with 1.0 part by weightof ion-exchanged water and thereafter with 0.3 part by weight of silicondioxide (Aerosil 200 produced by Nippon Aerosil Co., Ltd.) as aninorganic powder, thus obtaining a particulate water-absorbingcomposition (20). The resultant particulate water-absorbing composition(20) had a weight-average particle diameter of 295 μm, in which theratio of particles having particle diameters of smaller than 106 μm was5 weight %.

Example 21

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofbamboo cuticle (product obtained by pulverizing “Bamboo Cuticle Powder(trade name) produced by Ban Co., Ltd. (address: 1-98, Tsudakaigan-cho,Tokushima-shi, Tokushima Prefecture, Japan)” with a hammer mill; thispulverized product of Bamboo Cuticle Powder had a water content of 7.0%,and a particle diameter 300 μm-passed product thereof was used) as aplant powder and further with 1.0 part by weight of ion-exchanged water,thus obtaining a particulate water-absorbing composition (21). Theresultant particulate water-absorbing composition (21) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 5 weight%.

Example 22

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofresidue of extraction from coffee (product obtained by adding 50 g of“Maxim ORIGINAL/original (product name: Regular Coffee) sold byAjinomoto Co., Ltd. (address: 1-15-1, Kyobashi, Chuo-ku, TokyoPrefecture, Japan)” into 500 g of ion-exchanged water of about 80° C. tostir them together for 1 hour, and then filtrating the resultantmixture, and then vacuum-drying the filtered-off residue (namely, theresidue of extraction from coffee) at 60° C., and then pulverizing thedried product with a hammer mill; this pulverized dried product of theresidue of extraction from coffee had a water content of 4.1%, and aparticle diameter 850 μm-passed product thereof was used) as a plantpowder and further with 1.0 part by weight of ion-exchanged water, thusobtaining a particulate water-absorbing composition (22). The resultantparticulate water-absorbing composition (22) had a weight-averageparticle diameter of 295 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 5 weight %.

Example 23

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight ofstrained grape lees (product obtained by pulverizing commonlycommercially available fruit of Delaware trees with a mixer, and thenfiltrating the pulverized product, and then vacuum-drying thefiltered-off residue (namely, the strained grape lees) at 60° C., andthen further pulverizing the dried product with a hammer mill; thispulverized dried product of the strained grape lees had a water contentof 7.1%, and a particle diameter 500 μm-passed product thereof was used)as a plant powder and further with 1.0 part by weight of ion-exchangedwater, thus obtaining a particulate water-absorbing composition (23).The resultant particulate water-absorbing composition (23) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 5 weight%.

Example 24

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofpersimmon (product obtained by removing leaves and seeds from commonlycommercially available persimmon fruits (hira (in Japanese) persimmonfrom Wakayama Prefecture, Japan), and then pulverizing the resultantresidue with a mixer, and then vacuum-drying the pulverized product at60° C., and then cutting the dried product into as small pieces aspossible with scissors, and then pulverizing the resultant pieces with ahammer mill; this pulverized dried product of persimmon had a watercontent of 6.4%, and a particle diameter 850 μm-passed product thereofwas used) as a plant powder and further with 1.0 part by weight ofion-exchanged water, thus obtaining a particulate water-absorbingcomposition (24). The resultant particulate water-absorbing composition(24) had a weight-average particle diameter of 295 μm, in which theratio of particles having particle diameters of smaller than 106 μm was5 weight %.

Example 25

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 1.0 part by weight ofmugwort (product obtained by pulverizing leaves of mugwort with a mixer,and then vacuum-drying the pulverized product at 60° C., and thenfurther pulverizing the dried product with a hammer mill; this mugwortpowder had a water content of 7.3%, and a particle diameter 300μm-passed product thereof was used) as a plant powder and further with1.0 part by weight of ion-exchanged water, thus obtaining a particulatewater-absorbing composition (25). The resultant particulatewater-absorbing composition (25) had a weight-average particle diameterof 360 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 4 weight %.

Example 26

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 1.0 part by weight ofbamboo (product obtained by pulverizing “Bamboo Powder (trade name)produced by Ban Co., Ltd. (address: 1-98, Tsudakaigan-cho,Tokushima-shi, Tokushima Prefecture, Japan)” with a hammer mill; thispulverized product of Bamboo Powder had a water content of 7.9%, and aparticle diameter 500 μm-passed product thereof was used) as a plantpowder and further with 1.0 part by weight of ion-exchanged water, thusobtaining a particulate water-absorbing composition (26). The resultantparticulate water-absorbing composition (26) had a weight-averageparticle diameter of 360 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 4 weight %.

Example 27

An amount of 100 parts by weight of the water-absorbent resin (2) asobtained in Referential Example 2 was blended with 1.0 part by weight ofwakame (in Japanese) seaweed (product obtained by cutting “Cut Wakame(product name: Dry Wakame) sold by Nagao Foods Co., Ltd.(address: 295,Nobesue, Himeji-shi, Hyogo Prefecture, Japan)” into as small pieces aspossible with scissors, and then pulverizing the resultant pieces with ahammer mill; this pulverized product of wakame (in Japanese) seaweed hada water content of 9.5%, and a particle diameter 850 μm-passed productthereof was used) as a plant powder and further with 1.0 part by weightof ion-exchanged water, thus obtaining a particulate water-absorbingcomposition (27). The resultant particulate water-absorbing composition(27) had a weight-average particle diameter of 360 μm, in which theratio of particles having particle diameters of smaller than 106 μm was4 weight %.

Comparative Examples 1 to 31

The kinds of the water-absorbent resins, plant powders, and additives asused are shown together in Table 2. The properties and the deodorizingeffects of comparative particulate water-absorbing compositions (1 to31) are shown together in Tables 5 and 6. In addition, some evaluationsof the absorption properties of comparative absorbent articles (1 to 31)including the comparative particulate water-absorbing compositions (1 to31) are shown together in Table 7.

Hereinafter, production processes of the comparative water-absorbingcompositions (1 to 31) are explained.

Comparative Example 1

The water-absorbent resin (1) as obtained in Referential Example 1 wasregarded as a comparative particulate water-absorbing composition (1).The resultant comparative particulate water-absorbing composition (1)had a weight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 6 weight%.

Comparative Example 2

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.5 part by weight ofcommercially available deodorant comprising a green tea extract(Flavonoid-B produced by Daiichi Kasei Sangyo Co., Ltd.) to obtain acomparative particulate water-absorbing composition (2). The resultantcomparative particulate water-absorbing composition (2) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 6 weight%.

Comparative Example 3

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 10 parts by weight ofcommercially available deodorant comprising a green tea extract(Flavonoid-B produced by Daiichi Kasei Sangyo Co., Ltd.) to obtain acomparative particulate water-absorbing composition (3). The resultantcomparative particulate water-absorbing composition (3) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 3 weight%.

Comparative Example 4

An amount of 100 parts by weight of the water-absorbent resin (3) asobtained in Referential Example 3 was blended with 0.5 part by weight ofpepper (White Pepper Powder produced by Takasago Spice Co., Ltd.; thisWhite Pepper Powder had a water content of 10.3%, and a particlediameter 300 μm-passed product thereof was used, and its volume-averageparticle diameter was 77 μm) as a plant powder by a dry blend method,thus obtaining a comparative particulate water-absorbing composition(4). The resultant comparative particulate water-absorbing composition(4) had a weight-average particle diameter of 360 μm, in which the ratioof particles having particle diameters of smaller than 106 μm was 5weight %.

Comparative Example 5

An amount of 100 parts by weight of the water-absorbent resin (4) asobtained in Referential Example 4 was blended with 0.5 part by weight ofparsley (Parsley Powder CP produced by Yasuma Co., Ltd.; this ParsleyPowder CP had a water content of 6.7%, and a particle diameter 300μm-passed product thereof was used, and its volume-average particlediameter was 142 μm) as a plant powder by a dry blend method, thusobtaining a comparative particulate water-absorbing composition (5). Theresultant comparative particulate water-absorbing composition (5) had aweight-average particle diameter of 440 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 3 weight%.

Comparative Example 6

An amount of 100 parts by weight of the water-absorbent resin (5) asobtained in Referential Example 5 was blended with 0.5 part by weight ofpepper (White Pepper Powder produced by Takasago Spice Co., Ltd.; thisWhite Pepper Powder had a water content of 10.3%, and a particlediameter 300 μm-passed product thereof was used) as a plant powder by adry blend method, thus obtaining a comparative particulatewater-absorbing composition (6). The resultant comparative particulatewater-absorbing composition (6) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 6 weight %.

Comparative Example 7

An amount of 100 parts by weight of the water-absorbent resin (5) asobtained in Referential Example 5 was blended with 0.5 part by weight ofparsley (Parsley Powder CP produced by Yasuma Co., Ltd.; this ParsleyPowder CP had a water content of 6.7%, and a particle diameter 300μm-passed product thereof was used) as a plant powder by a dry blendmethod, thus obtaining a comparative particulate water-absorbingcomposition (7). The resultant comparative particulate water-absorbingcomposition (7) had a weight-average particle diameter of 295 μm, inwhich the ratio of particles having particle diameters of smaller than106 μm was 6 weight %.

Comparative Example 8

An amount of 100 parts by weight of the water-absorbent resin (3) asobtained in Referential Example 3 was blended with 0.5 part by weight ofgreen tea (product obtained by pulverizing “green tea (name of rawmaterial) sold by Nishie Corporation (address: 1652-3,Kakiuchikita-machi, Aboshi-ku, Himeji-shi, Hyogo Prefecture, Japan)”with a hammer mill; this pulverized product of green tea had a watercontent of 2.0%, and a particle diameter 850 μm-passed product thereofwas used, and its volume-average particle diameter was 287 μm) as aplant powder by a dry blend method, thus obtaining a comparativeparticulate water-absorbing composition (8). The resultant comparativeparticulate water-absorbing composition (8) had a weight-averageparticle diameter of 360 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 5 weight %.

Comparative Example 9

An amount of 100 parts by weight of the water-absorbent resin (4) asobtained in Referential Example 4 was blended with 0.5 part by weight ofa dried product of the residue of extraction from green tea (productobtained by adding 10 g of “green tea (name of raw material) sold byNishie Corporation (address: 1652-3, Kakiuchikita-machi, Aboshi-ku,Himeji-shi, Hyogo Prefecture, Japan)” into 500 g of ion-exchanged waterof about 95° C. to blend them together, and then filtrating theresultant mixture after 5 minutes, and then vacuum-drying thefiltered-off residue (namely, the residue of extraction from green tea)at 60° C., and then pulverizing the dried product with a hammer mill;this pulverized dried product of the residue of extraction from greentea had a water content of 6.3%, and a particle diameter 850 μm-passedproduct thereof was used, and its volume-average particle diameter was346 μm) as a plant powder by a dry blend method, thus obtaining acomparative particulate water-absorbing composition (9). The resultantcomparative particulate water-absorbing composition (9) had aweight-average particle diameter of 440 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 3 weight%.

Comparative Example 10

An amount of 100 parts by weight of the water-absorbent resin (5) asobtained in Referential Example 5 was blended with 50 parts by weight ofgreen tea (green tea (name of raw material) sold by Nishie Corporation(address: 1652-3, Kakiuchikita-machi, Aboshi-ku, Himeji-shi, HyogoPrefecture, Japan); a particle diameter 600 μm-passed product thereofwas used) as a plant powder by a dry blend method, thus obtaining acomparative particulate water-absorbing composition (10). The resultantcomparative particulate water-absorbing composition (10) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 8 weight%.

Comparative Example 11

An amount of 100 parts by weight of the water-absorbent resin (5) asobtained in Referential Example 5 was blended with 0.5 part by weight ofmandarin orange peel (product obtained by peeling a commonlycommercially available mandarin orange (from Arita, Japan), and thenpulverizing the resultant peel with a mixer, and then vacuum-drying thepulverized peel at 60° C., and then further pulverizing the driedproduct with a hammer mill; this pulverized dried product of mandarinorange peel had a water content of 4.5%, and a particle diameter 850μm-passed product thereof was used) as a plant powder and further with1.0 part by weight of ion-exchanged water, thus obtaining a comparativeparticulate water-absorbing composition (11). The resultant comparativeparticulate water-absorbing composition (11) had a weight-averageparticle diameter of 295 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 5 weight %.

Comparative Example 12

An amount of 100 parts by weight of the water-absorbent resin (5) asobtained in Referential Example 5 was blended with 0.5 part by weight ofstrained grape lees (product obtained by pulverizing commonlycommercially available fruit of Delaware trees with a mixer, and thenfiltrating the pulverized product, and then vacuum-drying thefiltered-off residue (namely, the strained grape lees) at 60° C., andthen further pulverizing the dried product with a hammer mill; thispulverized dried product of the strained grape lees had a water contentof 7.1%, and a particle diameter 500 μm-passed product thereof was used)as a plant powder and further with 1.0 part by weight of ion-exchangedwater, thus obtaining a comparative particulate water-absorbingcomposition (12). The resultant comparative particulate water-absorbingcomposition (12) had a weight-average particle diameter of 295 μm, inwhich the ratio of particles having particle diameters of smaller than106 μm was 4 weight %.

Comparative Example 13

An amount of 100 parts by weight of the water-absorbent resin (5) asobtained in Referential Example 5 was blended with 1.0 part by weight ofpersimmon (product obtained by removing leaves and seeds from commonlycommercially available persimmon fruits (hira (in Japanese) persimmonfrom Wakayama Prefecture, Japan), and then pulverizing the resultantresidue with a mixer, and then vacuum-drying the pulverized product at60° C., and then cutting the dried product into as small pieces aspossible with scissors, and then pulverizing the resultant pieces with ahammer mill; this pulverized dried product of persimmon had a watercontent of 6.4%, and a particle diameter 850 μm-passed product thereofwas used) as a plant powder and further with 1.0 part by weight ofion-exchanged water, thus obtaining a comparative particulatewater-absorbing composition (13). The resultant comparative particulatewater-absorbing composition (13) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 5 weight %.

Comparative Example 14

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.5 parts by weightof cellulose powder (KC Flock W-200G produced by Nippon Seishi Co.,Ltd.) by a dry blend method, thus obtaining a comparative particulatewater-absorbing composition (14). The resultant comparative particulatewater-absorbing composition (14) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 8 weight %.

Comparative Example 15

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.5 parts by weightof cellulose powder (KC Flock W-400G produced by Nippon Seishi Co.,Ltd.) by a dry blend method, thus obtaining a comparative particulatewater-absorbing composition (15). The resultant comparative particulatewater-absorbing composition (15) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 8 weight %.

Comparative Example 16

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 20 parts by weight ofcellulose powder (KC Flock W-400G produced by Nippon Seishi Co., Ltd.)by a dry blend method, thus obtaining a comparative particulatewater-absorbing composition (16). The resultant comparative particulatewater-absorbing composition (16) had a weight-average particle diameterof 260 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 24 weight %.

Comparative Example 17

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofactivated carbon (Shirasagi C produced by Takeda Chemical Industries,Ltd.) by a dry blend method, thus obtaining a comparative particulatewater-absorbing composition (17). The resultant comparative particulatewater-absorbing composition (17) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 7 weight %.

Comparative Example 18

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight oftannic acid (Hi Tannic Acid produced by Dainippon Seiyaku Co., Ltd.) and1.0 part by weight of silicate-salt-mineral-based deodorant (MizukaniteHP produced by Mizusawa Kagaku Kogyo Co., Ltd.), thus obtaining acomparative particulate water-absorbing composition (18). The resultantcomparative particulate water-absorbing composition (18) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 8 weight%.

Comparative Example 19

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight ofcommercially available deodorant comprising a green tea extract(Flavonoid-B produced by Daiichi Kasei Sangyo Co., Ltd.) and 1.0 part byweight of silicate-salt-mineral-based deodorant (Mizukanite HP producedby Mizusawa Kagaku Kogyo Co., Ltd.), thus obtaining a comparativeparticulate water-absorbing composition (19). The resultant comparativeparticulate water-absorbing composition (19) had a weight-averageparticle diameter of 295 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 8 weight %.

Comparative Example 20

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 1.0 part by weight oftannic acid (Hi Tannic Acid produced by Dainippon Seiyaku Co., Ltd.) and9.0 parts by weight of silicate-salt-mineral-based deodorant (MizukaniteHP produced by Mizusawa Kagaku Kogyo Co., Ltd.), thus obtaining acomparative particulate water-absorbing composition (20). The resultantcomparative particulate water-absorbing composition (20) had aweight-average particle diameter of 290 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 11 weight%.

Comparative Example 21

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 2 parts by weight ofconiferous-tree-extract-supported type deodorant (Isohiba 82 produced byEnsuiko Seito Co., Ltd.), thus obtaining a comparative particulatewater-absorbing composition (21). The resultant comparative particulatewater-absorbing composition (21) had a weight-average particle diameterof 295 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 8 weight %.

Comparative Example 22

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.4 part by weight ofcommercially available Hiba arbor-vitae oil, thus obtaining acomparative particulate water-absorbing composition (22). The resultantcomparative particulate water-absorbing composition (22) had aweight-average particle diameter of 295 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 6 weight%.

Comparative Example 23

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 100 parts by weightof coniferous-tree-extract-supported type deodorant (Isohiba 82 producedby Ensuiko Seito Co., Ltd.), thus obtaining a comparative particulatewater-absorbing composition (23). The resultant comparative particulatewater-absorbing composition (23) had a weight-average particle diameterof 205 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 45 weight %.

Comparative Example 24

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 20 parts by weight ofcommercially available Hiba arbor-vitae oil, thus obtaining acomparative particulate water-absorbing composition (24).

Comparative Example 25

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 0.4 part by weight ofcommercially available rosemary, thus obtaining a comparativeparticulate water-absorbing composition (25). The resultant comparativeparticulate water-absorbing composition (25) had a weight-averageparticle diameter of 295 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 6 weight %.

Comparative Example 26

An amount of 100 parts by weight of the water-absorbent resin (1) asobtained in Referential Example 1 was blended with 10 parts by weight ofcommercially available rosemary, thus obtaining a comparativeparticulate water-absorbing composition (26). The resultant comparativeparticulate water-absorbing composition (26) had a weight-averageparticle diameter of 295 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 5 weight %.

Comparative Example 27

An amount of 100 parts by weight of konjak (konnyaku) (in Japanese)(devil's tongue) powder, as a water-absorbent resin, was blended with0.5 part by weight of ginger (Ginger Powder produced by Takasago SpiceCo., Ltd.; this Ginger Powder had a water content of 9.1%, and aparticle diameter 300 μm-passed product thereof was used) as a plantpowder by a dry blend method, thus obtaining a comparative particulatewater-absorbing composition (27). The resultant comparative particulatewater-absorbing composition (27) had a weight-average particle diameterof 220 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 4 weight %.

Comparative Example 28

An amount of 100 parts by weight of konjak (konnyaku) (in Japanese)(devil's tongue) powder, as a water-absorbent resin, was blended with0.5 part by weight of black tea (product obtained by pulverizing “LiptonYELLOW LABEL (trade name) sold by Nippon Lever Co., Ltd. PT (address:2-22-3, Shibuya, Shibuya-ku, Tokyo Prefecture, Japan)” with a hammermill; this pulverized product of black tea had a water content of 6.8%,and a particle diameter 600 μm-passed product thereof was used) as aplant powder by a dry blend method, thus obtaining a comparativeparticulate water-absorbing composition (28). The resultant comparativeparticulate water-absorbing composition (28) had a weight-averageparticle diameter of 220 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 4 weight %.

Comparative Example 29

An amount of 100 parts by weight of Nonionlex NA-150M (produced by ShowaDenko Corporation), as a water-absorbent resin, was blended with 0.5part by weight of ginger (Ginger Powder produced by Takasago Spice Co.,Ltd.; this Ginger Powder had a water content of 9.1%, and a particlediameter 300 μm-passed product thereof was used) as a plant powder by adry blend method, thus obtaining a comparative particulatewater-absorbing composition (29). The resultant comparative particulatewater-absorbing composition (29) had a weight-average particle diameterof 490 μm, in which the ratio of particles having particle diameters ofsmaller than 106 μm was 2 weight %.

Comparative Example 30

An amount of 100 parts by weight of Nonionlex NA-150M (produced by ShowaDenko Corporation), as a water-absorbent resin, was blended with 0.5part by weight of black tea (product obtained by pulverizing “LiptonYELLOW LABEL (trade name) sold by Nippon Lever Co., Ltd. PT (address:2-22-3, Shibuya, Shibuya-ku, Tokyo Prefecture, Japan)” with a hammermill; this pulverized product of black tea had a water content of 6.8%,and a particle diameter 600 μm-passed product thereof was used) as aplant powder by a dry blend method, thus obtaining a comparativeparticulate water-absorbing composition (30). The resultant comparativeparticulate water-absorbing composition (30) had a weight-averageparticle diameter of 490 μm, in which the ratio of particles havingparticle diameters of smaller than 106 μm was 2 weight %.

Comparative Example 31

An amount of 100 parts by weight of Nonionlex NA-150M (produced by ShowaDenko Corporation), as a water-absorbent resin, was blended with 1.0part by weight of sea tangle (product obtained by cutting “Hidaka KizamiWakakombu (product name) produced by Maruzen Naya Shoten (address: 28-1,Shinkawa-cho, Hakodate-shi, Hokkaido Prefecture, Japan)” into as smallpieces as possible with scissors, and then pulverizing the resultantpieces with a hammer mill; this pulverized product of sea tangle had awater content of 9.9%, and a particle diameter 850 μm-passed productthereof was used) as a plant powder by a dry blend method, thusobtaining a comparative particulate water-absorbing composition (31).The resultant comparative particulate water-absorbing composition (31)had a weight-average particle diameter of 490 μm, in which the ratio ofparticles having particle diameters of smaller than 106 μm was 2 weight%.

TABLE 1 Water-absorbent Kind of plant powder or additive Water-absorbingExample resin I II composition  1 Water-absorbent resin (1) Pepper —Water-absorbing composition (1)   2 Water-absorbent resin (1) Pepper —Water-absorbing composition (2)   3 Water-absorbent resin (1) Japanesepepper — Water-absorbing composition (3)   4 Water-absorbent resin (1)Ginger — Water-absorbing composition (4)   5 Water-absorbent resin (2)Capsicum — Water-absorbing composition (5)   6 Water-absorbent resin (2)Parsley — Water-absorbing composition (6)   7 Water-absorbent resin (2)Parsley — Water-absorbing composition (7)   8 Water-absorbent resin (1)Green tea — Water-absorbing composition (8)   9 Water-absorbent resin(1) Milled green tea — Water-absorbing composition (9)  10Water-absorbent resin (1) Green tea — Water-absorbing composition (10)11 Water-absorbent resin (1) Black tea — Water-absorbing composition(11) 12 Water-absorbent resin (1) Oolong tea — Water-absorbingcomposition (12) 13 Water-absorbent resin (2) Pu-erh tea —Water-absorbing composition (13) 14 Water-absorbent resin (2) Residue ofextraction from green tea — Water-absorbing composition (14) 15Water-absorbent resin (2) Residue of extraction from black tea —Water-absorbing composition (15) 16 Water-absorbent resin (2) Residue ofextraction from oolong tea — Water-absorbing composition (16) 17Water-absorbent resin (1) Citron — Water-absorbing composition (17) 18Water-absorbent resin (1) Lime peel — Water-absorbing composition (18)19 Water-absorbent resin (1) Mandarin orange peel — Water-absorbingcomposition (19) 20 Water-absorbent resin (1) Sea tangle —Water-absorbing composition (20) 21 Water-absorbent resin (1) Bamboocuticle — Water-absorbing composition (21) 22 Water-absorbent resin (1)Residue of extraction from coffee — Water-absorbing composition (22) 23Water-absorbent resin (1) Strained grape lees — Water-absorbingcomposition (23) 24 Water-absorbent resin (1) Persimmon —Water-absorbing composition (24) 25 Water-absorbent resin (2) Mugwort —Water-absorbing composition (25) 26 Water-absorbent resin (2) Bamboo —Water-absorbing composition (26) 27 Water-absorbent resin (2) Wakameseaweed — Water-absorbing composition (27)

TABLE 2 Comparative Water-absorbent Kind of plant powder or additiveWater-absorbing Example resin I II composition  1 Water-absorbent resin(1) — — Comparative water-absorbing composition (1)   2 Water-absorbentresin (1) Green tea extract — Comparative water-absorbing composition(2)   3 Water-absorbent resin (1) Green tea extract — Comparativewater-absorbing composition (3)   4 Water-absorbent resin (3) Pepper —Comparative water-absorbing composition (4)   5 Water-absorbent resin(4) Parsley — Comparative water-absorbing composition (5)   6Water-absorbent resin (5) Pepper — Comparative water-absorbingcomposition (6)   7 Water-absorbent resin (5) Parsley — Comparativewater-absorbing composition (7)   8 Water-absorbent resin (3) Green tea— Comparative water-absorbing composition (8)   9 Water-absorbent resin(4) Residue of extraction from green tea — Comparative water-absorbingcomposition (9)  10 Water-absorbent resin (5) Green tea — Comparativewater-absorbing composition (10) 11 Water-absorbent resin (5) Mandarinorange peel — Comparative water-absorbing composition (11) 12Water-absorbent resin (5) Strained grape lees — Comparativewater-absorbing composition (12) 13 Water-absorbent resin (5) Persimmon— Comparative water-absorbing composition (13) 14 Water-absorbent resin(1) Cellulose powder — Comparative water-absorbing composition (14) 15Water-absorbent resin (1) Cellulose powder — Comparative water-absorbingcomposition (15) 16 Water-absorbent resin (1) Cellulose powder —Comparative water-absorbing composition (16) 17 Water-absorbent resin(1) Activated carbon — Comparative water-absorbing composition (17) 18Water-absorbing resin (1) Tannic acid Silicate salt Comparativewater-absorbing composition mineral (18) 19 Water-absorbent resin (1)Green tea extract Silicate salt Comparative water-absorbing compositionmineral (19) 20 Water-absorbent resin (1) Tannic acid Silicate saltComparative water-absorbing composition mineral (20) 21 Water-absorbentresin (1) Coniferous-tree-extract-supported type — Comparativewater-absorbing composition deoderant (21) 22 Water-absorbent resin (1)Hiba arbor-vitae oil — Comparative water-absorbing composition (22) 23Water-absorbent resin (1) Coniferous-tree-extract-supported type —Comparative water-absorbing composition deoderant (23) 24Water-absorbent resin (1) Hiba arbor-vitae oil — Comparativewater-absorbing composition (24) 25 Water-absorbent resin (1) Rosemary —Comparative water-absorbing composition (25) 26 Water-absorbent resin(1) Rosemary — Comparative water-absorbing composition (26) 27 Konjak(konnyaku) powder Ginger — Comparative water-absorbing composition (27)28 Konjak (konnyaku) pwder Black tea — Comparative water-absorbingcomposition (28) 29 Nonionlex Ginger — Comparative water-absorbingcomposition (29) 30 Nonionlex Black tea — Comparative water-absorbingcomposition (30) 31 Nonionlex Sea tangle — Comparative water-absorbingcomposition (31)

TABLE 3 Absorption Initial suction Suction power Suction indexAbsorption Color- capacity power under load under load under load ratedifference Example (g/g) (g/g) (g/g) (g/g) (seconds) L a b 1 33 10 11 2137 87.32 −0.51 7.35 2 33 10 11 21 37 86.01 −0.56 7.70 3 33 10 11 21 3781.64 0.29 7.32 4 32 9 10 19 29 87.70 −0.42 9.21 5 27 9 11 20 50 80.803.06 10.84 6 27 9 11 20 50 74.80 −3.27 8.66 7 27 9 11 20 50 70.56 −3.929.60 8 33 10 11 21 37 84.10 −0.67 5.82 9 33 10 11 21 37 78.86 −1.25 9.2210 33 10 11 21 37 71.88 −1.83 10.01 11 33 10 11 21 37 72.58 0.63 5.02 1233 10 11 21 37 85.03 −0.16 5.71 13 27 9 11 20 50 76.42 0.33 4.26 14 27 911 20 50 85.89 −0.51 5.98 15 26 8 10 18 42 72.01 1.09 5.67 16 27 9 11 2050 73.22 0.51 4.92 17 33 10 11 21 37 87.28 −0.86 9.54 18 33 10 11 21 3786.95 −0.92 6.92 19 32 9 10 19 29 86.02 −0.38 9.69 20 32 9 10 19 2983.36 −0.98 6.43 21 33 10 11 21 37 82.48 −2.05 11.41 22 33 10 11 21 3777.20 0.96 6.97 23 33 10 11 21 37 79.08 0.68 3.55 24 33 10 11 21 3786.30 −0.31 7.07 25 27 9 11 20 50 60.94 −4.77 9.97 26 27 9 11 20 5086.19 −0.18 8.96 27 27 9 11 20 50 74.16 −2.41 5.83

TABLE 4 Deodorizing Offensive-odor removal ratio Powder effect (%)Offensive-odor Example odor Initial 3 hours 6 hours Hydrogen sulfideMethylmercaptan Ammonia removal index Gel stability 1 0.4 2.4 2.5 2.742.8 53.0 99.9 183 Δ 2 0.6 2.1 2.3 2.4 54.1 54.9 99.9 199 ∘ 3 0.7 1.61.7 1.8 61.1 89.0 99.9 275 ∘ 4 1.3 1.5 1.7 2.6 60.0 82.2 100.0 260 ∘ 51.8 1.6 1.6 1.7 81.7 85.6 99.9 291 ∘ 6 1.8 1.9 2.3 3.0 77.7 95.1 99.9306 ∘ 7 1.9 1.8 2.4 3.1 82.5 96.4 99.9 314 ∘ 8 1.5 2.2 2.4 2.8 53.5 56.199.9 201 ∘ 9 1.4 1.8 2.0 2.3 65.0 72.0 99.9 245 ∘ 10 1.9 1.8 1.9 2.073.1 79.2 99.8 269 ∘ 11 1.2 2.2 2.2 2.2 74.1 78.1 99.9 268 ∘ 12 0.8 2.42.4 2.6 58.6 66.2 99.9 227 ∘ 13 0.9 2.7 2.7 3.1 89.3 96.4 99.9 321 ∘ 141.0 2.4 2.7 2.9 47.2 53.8 99.9 189 ∘ 15 1.4 2.5 2.6 2.8 67.8 72.3 99.9249 ∘ 16 1.3 2.4 2.6 2.9 52.1 64.7 99.9 217 ∘ 17 1.6 2.0 2.3 2.5 57.872.2 99.9 238 ∘ 18 1.3 2.3 2.4 2.6 49.5 70.3 99.9 225 ∘ 19 1.7 2.0 2.12.4 87.1 90.2 99.9 306 ∘ 20 0.7 2.4 2.4 2.9 86.9 79.4 99.9 284 ∘ 21 0.32.4 2.4 2.5 51.7 78.2 99.7 243 ∘ 22 2.4 2.0 2.3 2.5 59.7 60.5 99.9 217 ∘23 1.1 2.5 2.6 2.8 73.1 86.2 99.9 283 ∘ 24 1.0 2.5 2.7 2.9 78.1 86.999.9 290 ∘ 25 2.1 1.8 1.9 2.0 77.9 83.2 99.9 282 ∘ 26 0.8 2.3 2.3 2.353.1 76.2 99.9 241 ∘ 27 1.2 2.4 2.6 2.8 76.0 77.7 99.9 269 ∘

TABLE 5 Absorption Initial suction Suction power Suction indexAbsorption Color- Comparative capacity power under load under load underload rate difference Example (g/g) (g/g) (g/g) (g/g) (seconds) L a b 133 10 11 21 37 89.75 −0.33 7.09 2 33 10 11 21 37 88.92 −0.47 6.76 3 3210 11 21 33 88.30 −0.51 6.54 4 32 5 8 13 25 85.85 −0.47 7.75 5 32 5 8 1353 76.82 −2.84 8.20 6 45 3 6 9 21 86.23 −0.55 7.52 7 45 3 6 9 21 78.99−2.61 8.12 8 32 5 8 13 25 84.36 −0.58 5.85 9 32 5 8 13 53 86.02 −0.576.24 10 28 4 6 10 44 39.94 −4.42 10.58 11 45 3 6 9 21 88.38 −0.35 8.5112 45 3 6 9 21 79.59 0.72 3.65 13 45 3 6 9 21 86.43 −0.32 6.53 14 34 1012 22 43 89.15 −0.53 6.38 15 34 10 12 22 43 89.37 −0.43 6.17 16 29 10 1323 54 93.69 −0.18 5.24 17 33 10 11 21 37 25.80 0.13 0.49 18 34 10 11 2137 87.06 0.18 8.79 19 34 10 11 21 37 89.83 −0.30 5.69 20 30 10 11 21 3990.95 0.28 5.76 21 34 10 10 20 38 89.24 −1.10 7.92 22 36 10 11 21 3887.77 −0.63 6.89 23 18 2 8 10 196 95.14 −3.71 13.45 24 31 8 9 17 5575.66 −2.66 10.26 25 35 10 11 21 39 88.51 −0.46 6.59 26 35 10 11 21 3988.63 −0.41 7.22 27 18 4 5 9 100 74.69 0.84 15.25 28 18 4 5 9 100 73.250.89 16.52 29 23 2 5 7 65 90.80 −0.72 3.87 30 23 2 5 7 65 90.37 −0.684.02 31 23 2 5 7 65 90.51 −0.85 4.29

TABLE 6 Deodorizing Offensive-odor removal ratio Comparative Powdereffect (%) Offensive-odor Example odor Initial 3 hours 6 hours Hydrogensulfide Methylmercaptan Ammonia removal index Gel stability 1 0.2 4.04.3 5.0 35.2 46.5 99.9 162 x 2 0.7 3.3 3.6 4.0 — — — — x 3 1.3 3.0 3.33.8 — — — — x 4 0.6 4.1 4.1 4.2 30.4 38.6 99.4 140 x 5 1.7 3.9 4.0 4.236.8 45.3 99.5 161 x 6 0.4 4.0 4.0 4.3  7.1 25.9 98.6  89 x 7 1.8 4.04.0 4.2 26.6 37.7 98.8 134 x 8 1.6 3.2 3.3 3.8 38.4 49.7 99.1 171 x 91.2 3.4 3.5 3.9 34.6 46.4 99.3 161 x 10 4.1 3.2 3.3 3.6 — — — — x 11 1.53.4 3.6 3.9 30.2 32.9 98.6 129 x 12 0.7 3.5 3.8 4.0 24.7 32.8 98.9 122 x13 1.2 3.3 3.7 3.9 24.6 33.2 98.8 123 x 14 0.8 3.6 3.9 4.2 36.9 49.399.8 169 ∘ 15 0.9 3.3 3.5 4.0 36.7 48.7 99.8 168 ∘ 16 1.6 3.5 3.7 4.239.1 52.5 99.7 178 ∘ 17 0.7 1.8 2.0 2.4 — — — — ∘ 18 0.3 3.3 3.5 3.8 — —— — ∘ 19 0.4 3.1 3.4 3.7 — — — — ∘ 20 0.3 3.3 3.5 3.7 — — — — ∘ 21 4.31.0 1.3 1.8 — — — — Δ 22 4.5 1.0 1.0 1.4 — — — — Δ 23 5.0 1.0 1.0 1.2 —— — — x 24 5.0 1.0 1.0 1.2 — — — — x 25 4.7 1.8 2.0 2.3 — — — — Δ 26 5.01.0 1.0 1.3 — — — — x 27 4.6 3.6 3.8 4.4 64.8 13.9 16.7 104 x 28 4.5 3.73.9 4.3 65.2 16.4 18.3 110 x 29 1.2 4.4 4.4 4.5 11.0 21.8  0.0  56 x 301.1 4.3 4.5 4.6 10.5 20.3  0.0  52 x 31 1.2 4.5 4.6 4.8 13.2 20.6  0.0 56 x

TABLE 7 Evaluation of absorption Evaluation of absorption Evaluation ofabsorption properties of absorbent article properties of properties ofAmount as Amount of Substantial absorbent article absorbent articleWater-absorbing composition Absorption rate leaked out returningabsorption Deodorizing Dryness Deodorizing as used (seconds) (g) (g)quantity (g) test feeling effect Water-absorbing composition (3) 288 122 277 20 12 2.4 Water-absorbing composition (6) 401 2 50 248 24 14 16Water-absorbing composition (8) 312 3 22 275 24 14 21 Water-absorbingcomposition (10) 296 4 23 273 21 12 19 Water-absorbing composition (11)290 6 22 272 20 12 23 Water-absorbing composition (17) 315 4 24 272 2014 21 Water-absorbing composition (19) 338 3 43 254 2.0 12 21Water-absorbing composition (21) 295 5 22 273 23 1.2 24 Water-absorbingcomposition (25) 427 4 48 248 2.1 14 2.5 Water-absorbing composition(26) 422 3 48 249 21 14 16 Comparative water-absorbing 293 1 24 275 4012 43 composition (1) Comparative water-absorbing 2,102 30 40 230 36 2639 composition (6) Comparative water-absorbing 1,447 16 48 236 36 28 37composition (8) Comparative water-absorbing 305 7 22 271 40 14 45composition (14) Comparative water-absorbing 810 5 50 245 36 16 42composition (18) Comparative water-absorbing Not less than 97 55 148 443.0 44 composition (28) 3,600 Comparative water-absorbing Not less than67 57 176 42 30 43 composition (30) 3,600

INDUSTRIAL APPLICATION

The particulate water-absorbing composition according to the presentinvention is a new particulate water-absorbing composition which canprovide the deodorizing function to absorbent articles and exhibitsexcellent deodorizability and excellent absorption properties for a longtime. Although not clear, the cause is considered to be probably thatsince the water-absorbent resin is limited to such as exhibits thespecific absorption capacity, suction power under a load, and absorptionrate and since such a water-absorbent resin is provided with the plantpowder, the optimum balance between the action of effective componentsof the plant powder and the liquid absorption quantity upon contact withurine has been achieved.

In addition, since the above absorbent article according to the presentinvention includes the particulate water-absorbing composition accordingto the present invention and can therefore be provided with excellentdeodorizability of this composition, this absorbent article is favorablyusable particularly for sanitary materials such as disposable diapers,sanitary napkins, incontinent pads for adults, and diapers for adults,and can be what is able to retain an excellent wearing feeling for along time because of further being provided with the gel stability.

1. A particulate water-absorbing composition, which comprises aTracheophyta plant powder and a water-absorbent resin, wherein thewater-absorbent resin is a water-swellable and water-insolublecrosslinked poly(acrylic acid (salt)) polymer of 30 to 100 mol % inneutralization ratio having a surface portion and/or its vicinitytreated by crosslinking with a crosslinking agent and is contained in aproportion of not less than 70 weight % in the particulatewater-absorbing composition, and wherein the particulate water-absorbingcomposition is in the range of 100 to 600 μm in weight-average particlediameter and not more than 10 weight % in proportion of particles havingparticle diameters of smaller than 106 μm, and wherein the Tracheophytaplant powder passes through a mesh having a mesh opening size of 850 μm,and wherein the content of the Tracheophyta plant powder is in the rangeof 0.001 to 20 weight parts per 100 weight parts of the solid content ofthe water-absorbent resin, and wherein said content of the Tracheophytaplant powder is an amount effective for the particulate water-absorbingcomposition to exhibit an offensive-odor removal index of not less than180 wherein the offensive-odor removal index is represented by thefollowing equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.
 2. Aparticulate water-absorbing composition according to claim 1, whereinthe Tracheophyta plant is at least one kind of Tracheophyta plantselected from the group consisting of Gramineae, maple family,Ebenaceae, Betulaceae, Compositae, Lamiaceae, cryptomeria family,Umbelliferae, Rosaceae, Vitaceae, Japanese cypress family, pine family,Fagaceae, Brassicaceae, Leguminosae, Rutaceae, Cucurbitaceae,Solanaceae, Piperaceae, Zingiberaceae, Lauraceae, Malvaceae, andTheaceae.
 3. A particulate water-absorbing composition according toclaim 1, wherein the plant powder comprises a spice.
 4. A particulatewater-absorbing composition according to claim 3, wherein the spice hasa volume-average particle diameter of not larger than 850 μm.
 5. Aparticulate water-absorbing composition according to claim 1, whereinthe plant powder comprises a tea leaf and/or a residue of extractiontherefrom.
 6. A particulate water-absorbing composition according toclaim 5, wherein the tea leaf and/or residue of extraction therefrom hasa volume-average particle diameter of not larger than 500 μm.
 7. Aparticulate water-absorbing composition according to claim 1, whichexhibits an absorption capacity of 25 to 60 g/g for 0.9 weight % aqueoussodium chloride solution in 60 minutes, a suction index of not less than14 g/g for 25 g of artificial urine (25° C.) under a load of 1.96 kPa,and an absorption rate of not more than 60 seconds for physiologicalsalt solution of 30° C., wherein suction index (g/g) under load=initialsuction power (g/g) under load in 3 minutes+suction power (g/g) underload in 60 minutes, and wherein said artificial urine has the followingcomposition: 97.1 g of deionized water, 1.9 g of urea, 0.8 g of sodiumchloride, 0.1 g of magnesium chloride hexahydrate, and 0.1 g of calciumchloride.
 8. A particulate water-absorbing composition, which comprisesa Tracheophyta plant powder and a water-absorbent resin, wherein thewater-absorbent resin is a water-swellable and water-insolublecrosslinked poly(acrylic acid (salt)) polymer of 30 to 100 mol % inneutralization ratio and is contained in a proportion of not less than70 weight % in the particulate water-absorbing composition, and whereinthe particulate water-absorbing composition is in the range of 100 to600 μm in weight-average particle diameter and not more than 10 weight %in proportion of particles having particle diameters of smaller than 106μm and exhibits an absorption capacity of 25 to 60 g/g for 0.9 weight %aqueous sodium chloride solution in 60 minutes, a suction index of notless than 14 g/g for 25 g of artificial urine (25° C.) under a load of1.96 kPa, and an absorption rate of not more than 60 seconds forphysiological salt solution of 30° C., wherein suction index (g/g) underload=initial suction power (g/g) under load in 3 minutes+suction power(g/g) under load in 60 minutes, and wherein said artificial urine hasthe following composition: 97.1 g of deionized water, 1.9 g of urea, 0.8g of sodium chloride, 0.1 g of magnesium chloride hexahydrate, and 0.1 gof calcium chloride, and wherein the Tracheophyta plant powder passesthrough a mesh having a mesh opening size of 850 μm; and wherein thecontent of the Tracheophyta plant powder is in the range of 0.001 to 20weight parts per 100 weight parts of the solid content of thewater-absorbent resin, and wherein said content of the Tracheophytaplant powder is an amount effective for the particulate water-absorbingcomposition to exhibit an offensive-odor removal index of not less than180 wherein the offensive-odor removal index is represented by thefollowing equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio.
 9. Aparticulate water-absorbing composition according to claim 1, which isused for sanitary materials.
 10. A process for producing a particulatewater-absorbing composition, which comprises the step of adding aTracheophyta plant powder to a water-absorbent resin in an amount of0.001 to 20 weight parts per 100 weight parts of the solid content ofthe water-absorbent resin, wherein said amount of the Tracheophyta plantpowder being added is an amount effective to provide the particulatewater-absorbing composition with offensive-odor removal properties,wherein the Tracheophyta plant powder passes through a mesh having amesh opening size of 850 μm, and wherein the water-absorbent resin is awater-swellable and water-insoluble crosslinked poly(acrylic acid(salt)) polymer of 30 to 100 mol % in neutralization ratio and is usedin an amount so as to be contained in a proportion of not less than 70weight % in the particulate water-absorbing composition and is in therange of 100 to 600 μm in weight-average particle diameter and not morethan 10 weight % in proportion of particles having particle diameters ofsmaller than 106 μm and exhibits an absorption capacity of 25 to 60 g/gfor 0.9 weight % aqueous sodium chloride solution in 60 minutes, asuction power of not less than 9 g/g for 25 g of artificial urine (25°C.) under a load of 1.96 kPa in 60 minutes, and an absorption rate ofnot more than 60 seconds for physiological salt solution of 30° C.,wherein said artificial urine has the following composition: 97.1 g ofdeionized water, 1.9 g of urea, 0.8 g of sodium chloride, 0.1 g ofmagnesium chloride hexahydrate, and 0.1 g of calcium chloride.
 11. Anabsorbent article, which comprises an absorbent layer, aliquid-permeable surface sheet, and a liquid-impermeable back sheet,wherein the absorbent layer includes the particulate water-absorbingcomposition as recited in claim
 1. 12. An absorbent structure, whichcomprises a hydrophilic fiber, a Tracheophyta plant powder, and awater-absorbent resin, wherein the water-absorbent resin is awater-swellable and water-insoluble crosslinked poly(acrylic acid(salt)) polymer of 30 to 100 mol % in neutralization ratio and is in therange of 100 to 600 μm in weight-average particle diameter and not morethan 10 weight % in proportion of particles having particle diameters ofsmaller than 106 μm and exhibits an absorption capacity of 25 to 60 g/gfor 0.9 weight % aqueous sodium chloride solution in 60 minutes, asuction power of not less than 9 g/g for 25 g of artificial urine (25°C.) under a load of 1.96 kPa in 60 minutes, and an absorption rate ofnot more than 60 seconds for physiological salt solution of 30° C.,wherein said artificial urine has the following composition: 97.1 g ofdeionized water, 1.9 g of urea, 0.8 g of sodium chloride, 0.1 g ofmagnesium chloride hexahydrate, and 0.1 g of calcium chloride, andwherein the Tracheophyta plant powder passes through a mesh having amesh opening size of 850 μm, and wherein the content of the Tracheophytaplant powder is in the range of 0.001 to 20 weight parts per 100 weightparts of the solid content of the water-absorbent resin, and whereinsaid content of the Tracheophyta plant powder is an amount effective fora particulate water-absorbing composition to exhibit an offensive-odorremoval index of not less than 180 as the particulate water-absorbingcomposition including a mixture of the Tracheophyta plant powder and thewater-absorbent resin, wherein the offensive-odor removal index isrepresented by the following equation:offensive-odor removal index=1.1×hydrogen sulfide removalratio+2.0×methylmercaptan removal ratio+0.3×ammonia removal ratio. 13.An absorbent structure according to claim 12, which comprises theparticulate water-absorbing composition in which the Tracheophyta plantpowder is held by the water-absorbent resin, wherein the weight ratio ofthe particulate water-absorbing composition to the total of thehydrophilic fiber and the particulate water-absorbing composition is notless than 0.3.
 14. A particulate water-absorbing composition accordingto claim 1, wherein the water-extractable content in the water-absorbentresin is not more than 50 weight %.
 15. A particulate water-absorbingcomposition according to claim 1, wherein the Tracheophyta plant powderis in the range of 1 to 50 (but not including 50) in aspect ratio wherethe aspect ratio is calculated by length/breadth where the length andbreadth are the dimensions of the Tracheophyta plant powder, and whereinthe water content of the Tracheophyta plant powder is not more than 40%.16. A particulate water-absorbing composition according to claim 8,which is used for sanitary materials.
 17. An absorbent article, whichcomprises an absorbent layer, a liquid-permeable surface sheet, and aliquid-impermeable back sheet, wherein the absorbent layer includes theparticulate water-absorbing composition as recited in claim
 8. 18. Aparticulate water-absorbing composition according to claim 8, whereinthe water-extractable content in the water-absorbent resin is not morethan 50 weight %.
 19. A particulate water-absorbing compositionaccording to claim 8, wherein the Tracheophyta plant powder is in therange of 1 to 50 (but not including 50) in aspect ratio where the aspectratio is calculated by length/breadth where the length and breadth arethe dimensions of the Tracheophyta plant powder, and wherein the watercontent of the Tracheophyta plant powder is not more than 40%.
 20. Aparticulate water-absorbing composition according to claim 1, whereinsaid Tracheophyta plant powder is a particulate and where saidwater-absorbent resin is a particulate, said composition comprising adry blend of said Tracheophyta plant powder and said water-absorbentresin.
 21. A particulate water-absorbing composition according to claim8, wherein said composition is a dry blend of said Tracheophyta plantpowder and said water-absorbent resin.
 22. A particulate water-absorbingcomposition according to claim 21, wherein said Tracheophyta plantpowder is a particulate and said water-absorbent resin is a particulate.23. A process for producing a particulate water-absorbing compositionaccording to claim 10, wherein said process comprises dry blending saidTracheophyta plant powder with said water-absorbent resin, wherein saidTracheophyta plant powder is a particulate and said water-absorbentresin is a particulate.
 24. A particulate water-absorbing compositionaccording to claim 1, further comprising an inorganic powder in anamount of 0.001 to 10 weight parts per 100 weight parts of thewater-absorbent resin.
 25. A particulate water-absorbing compositionaccording to claim 8, further comprising an inorganic powder in anamount of 0.001 to 10 weight parts per 100 weight parts of thewater-absorbent resin.
 26. A particulate water-absorbing compositionaccording to claim 1, which exhibits a color-difference (L, a, b) inwhich: L is not less than 40; the absolute value of a is not more than4; and b is in the range of 0 to
 15. 27. A particulate water-absorbingcomposition according to claim 8, which exhibits a color-difference (L,a, b) in which: L is not less than 40; the absolute value of a is notmore than 4; and b is in the range of 0 to
 15. 28. A particulatewater-absorbing composition according to claim 8, wherein theTracheophyta plant is at least one kind of Tracheophyta plant selectedfrom the group consisting of Gramineae, maple family, Ebenaceae,Betulaceae, Compositae, Lamiaceae, cryptomeria family, Umbelliferae,Rosaceae, Vitaceae, Japanese cypress family, pine family, Fagaceae,Brassicaceae, Leguminosae, Rutaceae, Cucurbitaceae, Solanaceae,Piperaceae, Zingiberaceae, Lauraceae, Malvaceae, and Theaceae.
 29. Aparticulate water-absorbing composition according to claim 8, whereinthe Tracheophyta plant powder comprises a spice wherein the spice has avolume-average particle diameter of not larger than 850 μm.
 30. Aparticulate water-absorbing composition according to claim 8, whereinthe Tracheophyta plant powder comprises a tea leaf and/or a residue ofextraction therefrom wherein the tea leaf and/or residue of extractiontherefrom has a volume-average particle diameter of not larger than 500μm.
 31. A particulate water-absorbing composition according to claim 3,wherein the spice is at least one member selected from the groupconsisting of peppers, Japanese peppers, ginger, capsicums, parsley, andJapanese horseradishes.
 32. A particulate water-absorbing compositionaccording to claim 29, wherein the spice is at least one member selectedfrom the group consisting of peppers, Japanese peppers, ginger,capsicums, parsley, and Japanese horseradishes.
 33. A particulatewater-absorbing composition according to claim 1, which has a powderodor strength of not more than
 2. 34. A particulate water-absorbingcomposition according to claim 8, which has a powder odor strength ofnot more than
 2. 35. A particulate water-absorbing composition accordingto claim 1, wherein the Tracheophyta plant powder is at least one memberselected from the group consisting of pepper, Japanese pepper, ginger,parsley, green tea, milled green tea, oolong tea, pu-erh tea, a residueof extraction from green tea, a residue of extraction from black tea, aresidue of extraction from oolong tea, citron, lime peel, mandarinorange peel, sea tangle, bamboo cuticle, a residue of extraction fromcoffee, strained grape lees, persimmon, mugwort, and bamboo.
 36. Aparticulate water-absorbing composition according to claim 8, whereinthe Tracheophyta plant powder is at least one member selected from thegroup consisting of pepper, Japanese pepper, ginger, parsley, green tea,milled green tea, oolong tea, pu-erh tea, a residue of extraction fromgreen tea, a residue of extraction from black tea, a residue ofextraction from oolong tea, citron, lime peel, mandarin orange peel, seatangle, bamboo cuticle, a residue of extraction from coffee, strainedgrape lees, persimmon, mugwort, and bamboo.
 37. A particulatewater-absorbing composition according to claim 1, wherein theTracheophyta plant powder is a bamboo powder.
 38. A particulatewater-absorbing composition according to claim 8, wherein theTracheophyta plant powder is a bamboo powder.
 39. A process forproducing a particulate water-absorbing composition according to claim10, wherein the Tracheophyta plant is at least one kind of Tracheophytaplant selected from the group consisting of Gramineae, maple family,Ebenaceae, Betulaceae, Compositae, Lamiaceae, cryptomeria family,Umbelliferae, Rosaceae, Vitaceae, Japanese cypress family, pine family,Fagaceae, Brassicaceae, Leguminosae, Rutaceae, Cucurbitaceae,Solanaceae, Piperaceae, Zingiberaceae, Lauraceae, Malvaceae, andTheaceae.
 40. A process for producing a particulate water-absorbingcomposition according to claim 10, wherein the Tracheophyta plant powdercomprises a spice wherein the spice has a volume-average particlediameter of not larger than 850 μm.
 41. A process for producing aparticulate water-absorbing composition according to claim 10, whereinthe Tracheophyta plant powder comprises a tea leaf and/or a residue ofextraction therefrom wherein the tea leaf and/or residue of extractiontherefrom has a volume-average particle diameter of not larger than 500μm.
 42. A process for producing a particulate water-absorbingcomposition according to claim 10, wherein the Tracheophyta plant powderis at least one member selected from the group consisting of pepper,Japanese pepper, ginger, parsley, green tea, milled green tea, oolongtea, pu-erh tea, a residue of extraction from green tea, a residue ofextraction from black tea, a residue of extraction from oolong tea,citron, lime peel, mandarin orange peel, sea tangle, bamboo cuticle, aresidue of extraction from coffee, strained grape lees, persimmon,mugwort, and bamboo.
 43. A particulate water-absorbing compositionaccording to claim 1, wherein said content of the Tracheophyta plantpowder is an amount effective for the particulate water-absorbingcomposition to remove hydrogen sulfide, methylmercaptan and ammonia froma liquid.
 44. A particulate water-absorbing composition according toclaim 8, wherein said content of the Tracheophyta plant powder is anamount effective for the particulate water-absorbing composition toremove hydrogen sulfide, methylmercaptan and ammonia from a liquid. 45.A process for producing a particulate water-absorbing compositionaccording to claim 10, wherein said amount of the Tracheophyta plantpowder being added is an amount effective for the particulatewater-absorbing composition to remove hydrogen sulfide, methylmercaptanand ammonia from a liquid.
 46. An absorbent structure according to claim12, wherein said content of the Tracheophyta plant powder is an amounteffective for the particulate water-absorbing composition to removehydrogen sulfide, methylmercaptan and ammonia from a liquid.